Some differences between English plural noun inflections and third singular verb inflections in the input: the contributions of frequency, sentence position, and duration

Verbs Matter: A Tutorial for Determining Verb Difficulty

PURPOSE

Research indicates that when teaching grammatical forms to children, the verbs used to model specific grammatical inflections matter. When learning grammatical forms, children have higher performance when they hear many unique verb forms that vary in their frequency and phonological complexity. In this tutorial, we demonstrate a method for identifying and characterizing a large number of verbs based on their frequency and complexity.

METHOD

We selected verbs from an open-access database of transcribed child language samples. We extracted verbs produced by 5- to 8.9-year-old children in four morphosyntactic contexts: regular past tense -ed, third person singular -s, is/are + verb+ing, and do/does questions. We ranked verbs based on their frequency of occurrence across transcripts. We also coded the phonological complexity of each verb. We coded each verb as high or low frequency and high or low phonological complexity.

RESULTS

The synthesis yielded 129 unique verbs used in the regular past tense -ed context, 107 verbs used in the third person singular -s context, 69 verbs used in the is/are + verb+ing context, and 16 verbs used in the do/does question context. We created tables for each form that include the frequency rankings and phonological complexity scores for every verb.

CONCLUSIONS

Clinicians may use the verb lists, frequency ratings, and phonological complexity scores to help identify verbs to incorporate into assessment and intervention sessions with children. Researchers and clinicians may use the step-by-step approach presented in the tutorial to identify verbs or other syntactic components used in different morphosyntactic contexts or produced by individuals of different demographics in different speaking contexts.

Testing the Representational Deficit Hypothesis: From the Aspect of Chinese Learners' Acquisition of Affixation '-s' for Third Person Singular Verbs and Plural Nouns

The persistent difficulty in making verbal inflections is commonly recognized for second language learners, especially for Chinese-speaking students. Researchers put forward different hypotheses to explain the problems in acquiring inflectional morphology. Among them, the representational deficit hypothesis deficit (RDH), advocated by Hawkins and Liszka, indicates that adult learners will fail to make inflectional morphology to interpret the corresponding syntactic feature if there is no counterpart system in their native language. In English, affix morpheme '-s' marks either third person singular (3SG) in the present tense or regular plural nouns. In contrast, Chinese is a language which lacks 3SG markings but presents the morpheme 'men' to reflect a plural feature for nouns with a human property. To test the applicability of the RDH in the domain of affix '-s' for English learners of Chinese, the present study observed the morphological inflections of the third person singular and plural '-s' in 33 Chinese EFL learners' written and spoken production tasks. The results show that the participants distinguished between the inflectional morphology in regular plural and 3SG thematic verb markings, which was compatible with the RDH. Additionally, other phenomena related to 3SG and plural morphological inflections provided strands of evidence for the RDH, for instance, L2 exposure age, a prominent overuse of plural '-s', and exceptional cases for more 3SG '-s' markings in the written data. Except for the account of morphosyntactic processes in the RDH, other factors, such as input frequency, difficulty of paradigm uniformity, and acquisition order, were referred to as the way that the L2 learners' acquisition of the morphological inflections was affected.

The duration of word-final /s/ differs across morphological categories in English: evidence from pseudowords

Previous research suggests that different types of word-final /s/ and /z/ (e.g. non-morphemic vs. plural or clitic morpheme) in English show realisational differences in duration. However, there is disagreement on the nature of these differences, as experimental studies have provided evidence for durational differences of the opposite direction as results from corpus studies (i.e. non-morphemic > plural > clitic /s/). The experimental study reported here focuses on four types of word-final /s/ in English, i.e. non-morphemic, plural, and is- and has-clitic /s/. We conducted a pseudoword production study with native speakers of Southern British English. The results show that non-morphemic /s/ is significantly longer than plural /s/, which in turn is longer than clitic /s/, while there is no durational difference between the two clitics. This aligns with previous corpus rather than experimental studies. Thus, the morphological category of a word-final /s/ appears to be a robust predictor for its phonetic realisation influencing speech production in such a way that systematic subphonemic differences arise. This finding calls for revisions of current models of speech production in which morphology plays no role in later stages of production.

Durational Differences of Word-Final /s/ Emerge From the Lexicon: Modelling Morpho-Phonetic Effects in Pseudowords With Linear Discriminative Learning

Recent research has shown that seemingly identical suffixes such as word-final /s/ in English show systematic differences in their phonetic realisations. Most recently, durational differences between different types of /s/ have been found to also hold for pseudowords: the duration of /s/ is longest in non-morphemic contexts, shorter with suffixes, and shortest in clitics. At the theoretical level such systematic differences are unexpected and unaccounted for in current theories of speech production. Following a recent approach, we implemented a linear discriminative learning network trained on real word data in order to predict the duration of word-final non-morphemic and plural /s/ in pseudowords using production data by a previous production study. It is demonstrated that the duration of word-final /s/ in pseudowords can be predicted by LDL networks trained on real word data. That is, duration of word-final /s/ in pseudowords can be predicted based on their relations to the lexicon.

The Acquisition of Productive Plural Morphology by Children With Hearing Loss

Purpose Normal-hearing (NH) children acquire plural morphemes at different rates, with the segmental allomorphs /-s, -z/ (e.g., cat-s) being acquired before the syllabic allomorph /-əz/ (e.g., bus-es). Children with hearing loss (HL) have been reported to show delays in the production of plural morphology, raising the possibility that this might be due to challenges acquiring different types of lexical/morphological representations. This study therefore examined the comprehension of plural morphology by 3- to 7-year-olds with HL and compared this with performance by their NH peers. We also investigated comprehension as a function of wearing hearing aids (HAs) versus cochlear implants (CIs). Method Participants included 129 NH children aged 3-5 years and 25 children with HL aged 3-7 years (13 with HAs, 12 with CIs). All participated in a novel word two-alternative forced-choice task presented on an iPad. The task tested comprehension of the segmental (e.g., teps, mubz) and syllabic (e.g., kosses) plural, as well as their singular counterparts (e.g., tep, mub, koss). Results While the children with NH were above chance for all conditions, those with HL performed at chance. As a group, the performance of the children with HL did not improve with age. However, results suggest possible differences between children with HAs and those with CIs, where those with HAs appeared to be in the process of developing representations of consonant-vowel-consonant singulars. Conclusions Results suggest that preschoolers with HL do not yet have a robust representation of plural morphology for words they have not heard before. However, those with HAs are beginning to access the singular/plural system as they get older.

Five overarching factors central to grammatical learning and treatment in children with developmental language disorder

BACKGROUND

During grammatical treatment of children with developmental language disorder (DLD), it is natural for therapists to focus on the grammatical details of the target language that give the children special difficulty. However, along with the language-specific features of the target (e.g., for English, add -s to verbs in present tense, third-person singular contexts), there are overarching factors that operate to render the children's learning task more, or less, challenging, depending on the particular target.

AIMS

To identify five such factors that can play a role in the grammatical learning of children with DLD. We use English as our example language and provide supporting evidence from a variety of other languages.

MAIN CONTRIBUTION

We show that the relative degree of English-speaking children's difficulty with particular grammatical details can be affected by the extent to which these details involve: (1) bare stems; (2) opportunities for grammatical case confusion; (3) prosodic challenges; (4) grammatical and lexical aspect; and (5) deviations from canonical word order.

CONCLUSIONS

During treatment, therapists will want to consider not only the English-specific features of grammatical targets but also how these more general factors can be taken into account to increase the children's success.

A multilinguistic analysis of spelling among children with cochlear implants

This study examines the spelling of nine elementary school children with cochlear implants (CIs) who use spoken language, and compares their performance with children who have typical hearing and children who are hard of hearing (HH). Compared to children with typical hearing, children with CIs did not produce a significantly different percentage of misspelled words (p = 0.431, d = 0.38), but their spelling errors comprised significantly lower percentages of homophone substitutions (p = 0.019, r = 0.61) and legal vowel errors (p = 0.011, r = 0.61). Children with CIs and children who are HH did not produce a significantly different percentage of misspelled words (p = 0.521, d = 0.31) or a significantly different distribution of categorical spelling errors. Results suggest that children with CIs utilize similar linguistic strategies as their peers who are HH but different strategies than peers with typical hearing when attempting to spell unfamiliar words.

Relationship of Grammatical Context on Children's Recognition of s/z-Inflected Words

BACKGROUND

Access to aided high-frequency speech information is currently assessed behaviorally using recognition of plural monosyllabic words. Because of semantic and grammatical cues that support word+morpheme recognition in sentence materials, the contribution of high-frequency audibility to sentence recognition is less than that for isolated words. However, young children may not yet have the linguistic competence to take advantage of these cues. A low-predictability sentence recognition task that controls for language ability could be used to assess the impact of high-frequency audibility in a context that more closely represents how children learn language.

PURPOSE

To determine if differences exist in recognition of s/z-inflected monosyllabic words for children with normal hearing (CNH) and children who are hard of hearing (CHH) across stimuli context (presented in isolation versus embedded medially within a sentence that has low semantic and syntactic predictability) and varying levels of high-frequency audibility (4- and 8-kHz low-pass filtered for CNH and 8-kHz low-pass filtered for CHH).

RESEARCH DESIGN

A prospective, cross-sectional design was used to analyze word+morpheme recognition in noise for stimuli varying in grammatical context and high-frequency audibility. Low-predictability sentence stimuli were created so that the target word+morpheme could not be predicted by semantic or syntactic cues. Electroacoustic measures of aided access to high-frequency speech sounds were used to predict individual differences in recognition for CHH.

STUDY SAMPLE

Thirty-five children, aged 5-12 yrs, were recruited to participate in the study; 24 CNH and 11 CHH (bilateral mild to severe hearing loss) who wore hearing aids (HAs). All children were native speakers of English.

DATA COLLECTION AND ANALYSIS

Monosyllabic word+morpheme recognition was measured in isolated and sentence-embedded conditions at a +10 dB signal-to-noise ratio using steady state, speech-shaped noise. Real-ear probe microphone measures of HAs were obtained for CHH. To assess the effects of high-frequency audibility on word+morpheme recognition for CNH, a repeated-measures ANOVA was used with bandwidth (8 kHz, 4 kHz) and context (isolated, sentence embedded) as within-subjects factors. To compare recognition between CNH and CHH, a mixed-model ANOVA was completed with context (isolated, sentence-embedded) as a within-subjects factor and hearing status as a between-subjects factor. Bivariate correlations between word+morpheme recognition scores and electroacoustic measures of high-frequency audibility were used to assess which measures might be sensitive to differences in perception for CHH.

RESULTS

When high-frequency audibility was maximized, CNH and CHH had better word+morpheme recognition in the isolated condition compared with sentence-embedded. When high-frequency audibility was limited, CNH had better word+morpheme recognition in the sentence-embedded condition compared with the isolated condition. CHH whose HAs had greater high-frequency speech bandwidth, as measured by the maximum audible frequency, had better word+morpheme recognition in sentences.

CONCLUSIONS

High-frequency audibility supports word+morpheme recognition within low-predictability sentences for both CNH and CHH. Maximum audible frequency can be used to estimate word+morpheme recognition for CHH. Low-predictability sentences that do not contain semantic or grammatical context may be of clinical use in estimating children's use of high-frequency audibility in a manner that approximates how they learn language.

Why do children pay more attention to grammatical morphemes at the ends of sentences?

Children pay more attention to the beginnings and ends of sentences rather than the middle. In natural speech, ends of sentences are prosodically and segmentally enhanced; they are also privileged by sensory and recall advantages. We contrasted whether acoustic enhancement or sensory and recall-related advantages are necessary and sufficient for the salience of grammatical morphemes at the ends of sentences. We measured 22-month-olds' listening times to grammatical and ungrammatical sentences with third person singular -s. Crucially, by cross-splicing the speech stimuli, acoustic enhancement and sensory and recall advantages were fully crossed. Only children presented with the verb in sentence-final position, a position with sensory and recall advantages, distinguished between the grammatical and ungrammatical sentences. Thus, sensory and recall advantages alone were necessary and sufficient to make grammatical morphemes at ends of sentences salient. These general processing constraints privilege ends of sentences over middles, regardless of the acoustic enhancement.

The Changing View of Input in the Treatment of Children With Grammatical Deficits

PURPOSE

The purpose of this article is to present 3 approaches that emphasize the role that input plays in the treatment of grammatical deficits in children with language impairments.

METHOD

These approaches-input informativeness, competing sources of input, and high variability-were selected because they go beyond issues of token frequency and emphasize instead type frequency, relative frequency, and frequency at an abstract as well as a concrete level of grammar. Each of these approaches can be applied to the grammatical deficits seen in children with specific language impairment and can be readily used with well-established procedures, such as focused stimulation and recasting.

RESULTS

Each approach is supported by a body of laboratory research with children with typical language skills, and the feasibility of each has been tested in studies with a treatment design. Furthermore, the assumptions of the 3 approaches are largely compatible, permitting application of combinations of these approaches without violating any of their principles.

CONCLUSION

The positive findings from each of these approaches should serve as a basis for further clinical research.

Language Outcomes in Young Children with Mild to Severe Hearing Loss

OBJECTIVES

This study examined the language outcomes of children with mild to severe hearing loss during the preschool years. The longitudinal design was leveraged to test whether language growth trajectories were associated with degree of hearing loss and whether aided hearing influenced language growth in a systematic manner. The study also explored the influence of the timing of hearing aid fitting and extent of use on children's language growth. Finally, the study tested the hypothesis that morphosyntax may be at particular risk due to the demands it places on the processing of fine details in the linguistic input.

DESIGN

The full cohort of children in this study comprised 290 children who were hard of hearing (CHH) and 112 children with normal hearing who participated in the Outcomes of Children with Hearing Loss (OCHL) study between the ages of 2 and 6 years. CHH had a mean better-ear pure-tone average of 47.66 dB HL (SD = 13.35). All children received a comprehensive battery of language measures at annual intervals, including standardized tests, parent-report measures, and spontaneous and elicited language samples. Principal components analysis supported the use of a single composite language score for each of the age levels (2, 3, 4, 5, and 6 years). Measures of unaided (better-ear pure-tone average, speech intelligibility index) and aided (residualized speech intelligibility index) hearing were collected, along with parent-report measures of daily hearing aid use time. Mixed modeling procedures were applied to examine the rate of change (227 CHH; 94 children with normal hearing) in language ability over time in relation to (1) degree of hearing loss, (2) aided hearing, (3) age of hearing aid fit and duration of use, and (4) daily hearing aid use. Principal components analysis was also employed to examine factor loadings from spontaneous language samples and to test their correspondence with standardized measures. Multiple regression analysis was used to test for differential effects of hearing loss on morphosyntax and lexical development.

RESULTS

Children with mild to severe hearing loss, on average, showed depressed language levels compared with peers with normal hearing who were matched on age and socioeconomic status. The degree to which CHH fell behind increased with greater severity of hearing loss. The amount of improved audibility with hearing aids was associated with differential rates of language growth; better audibility was associated with faster rates of language growth in the preschool years. Children fit early with hearing aids had better early language achievement than children fit later. However, children who were fit after 18 months of age improved in their language abilities as a function of the duration of hearing aid use. These results suggest that the language learning system remains open to experience provided by improved access to linguistic input. Performance in the domain of morphosyntax was found to be more delayed in CHH than their semantic abilities.

CONCLUSION

The data obtained in this study largely support the predictions, suggesting that mild to severe hearing loss places children at risk for delays in language development. Risks are moderated by the provision of early and consistent access to well-fit hearing aids that provide optimized audibility.

Effects of Type of Agreement Violation and Utterance Position on the Auditory Processing of Subject-Verb Agreement: An ERP Study

Previous ERP studies have often reported two ERP components-LAN and P600-in response to subject-verb (S-V) agreement violations (e.g., the boys (*) runs). However, the latency, amplitude and scalp distribution of these components have been shown to vary depending on various experiment-related factors. One factor that has not received attention is the extent to which the relative perceptual salience related to either the utterance position (verbal inflection in utterance-medial vs. utterance-final contexts) or the type of agreement violation (errors of omission vs. errors of commission) may influence the auditory processing of S-V agreement. The lack of reports on these effects in ERP studies may be due to the fact that most studies have used the visual modality, which does not reveal acoustic information. To address this gap, we used ERPs to measure the brain activity of Australian English-speaking adults while they listened to sentences in which the S-V agreement differed by type of agreement violation and utterance position. We observed early negative and positive clusters (AN/P600 effects) for the overall grammaticality effect. Further analysis revealed that the mean amplitude and distribution of the P600 effect was only significant in contexts where the S-V agreement violation occurred utterance-finally, regardless of type of agreement violation. The mean amplitude and distribution of the negativity did not differ significantly across types of agreement violation and utterance position. These findings suggest that the increased perceptual salience of the violation in utterance final position (due to phrase-final lengthening) influenced how S-V agreement violations were processed during sentence comprehension. Implications for the functional interpretation of language-related ERPs and experimental design are discussed.

An Introduction to the Outcomes of Children with Hearing Loss Study

The landscape of service provision for young children with hearing loss has shifted in recent years as a result of newborn hearing screening and the early provision of interventions, including hearing technologies. It is expected that early service provision will minimize or prevent linguistic delays that typically accompany untreated permanent childhood hearing loss. The post-newborn hearing screening era has seen a resurgence of interest in empirically examining the outcomes of children with hearing loss to determine if service innovations have resulted in expected improvements in children's functioning. The Outcomes of Children with Hearing Loss (OCHL) project was among these recent research efforts, and this introductory article provides background in the form of literature review and theoretical discussion to support the goals of the study. The Outcomes of Children with Hearing Loss project was designed to examine the language and auditory outcomes of infants and preschool-age children with permanent, bilateral, mild-to-severe hearing loss, and to identify factors that moderate the relationship between hearing loss and longitudinal outcomes. The authors propose that children who are hard of hearing experience limitations in access to linguistic input, which lead to a decrease in uptake of language exposure and an overall reduction in linguistic experience. The authors explore this hypothesis in relation to three primary factors that are proposed to influence children's access to linguistic input: aided audibility, duration and consistency of hearing aid use, and characteristics of caregiver input.

The role of sentence position, allomorph, and morpheme type on accurate use of s-related morphemes by children who are hard of hearing

PURPOSE

Production accuracy of s-related morphemes was examined in 3-year-olds with mild-to-severe hearing loss, focusing on perceptibility, articulation, and input frequency.

METHOD

Morphemes with /s/, /z/, and /ɪz/ as allomorphs (plural, possessive, third-person singular -s, and auxiliary and copula "is") were analyzed from language samples gathered from 51 children (ages: 2;10 [years;months] to 3;8) who are hard of hearing (HH), all of whom used amplification. Articulation was assessed via the Goldman-Fristoe Test of Articulation-Second Edition, and monomorphemic word final /s/ and /z/ production. Hearing was measured via better ear pure tone average, unaided Speech Intelligibility Index, and aided sensation level of speech at 4 kHz.

RESULTS

Unlike results reported for children with normal hearing, the group of children who are HH correctly produced the /ɪz/ allomorph more than /s/ and /z/ allomorphs. Relative accuracy levels for morphemes and sentence positions paralleled those of children with normal hearing. The 4-kHz sensation level scores (but not the better ear pure tone average or Speech Intelligibility Index), the Goldman-Fristoe Test of Articulation-Second Edition, and word final s/z use all predicted accuracy.

CONCLUSIONS

Both better hearing and higher articulation scores are associated with improved morpheme production, and better aided audibility in the high frequencies and word final production of s/z are particularly critical for morpheme acquisition in children who are HH.

Evaluation of three proposed markers for language impairment in English: a meta-analysis of diagnostic accuracy studies

PURPOSE

The goal of the study was to determine to what extent 3 proposed markers of language impairment (LI) in English (verb tense, nonword repetition, and sentence repetition) accurately distinguish affected and unaffected English-speaking individuals.

METHOD

Electronic databases were searched for diagnostic accuracy studies involving the 3 markers. Quality of relevant studies was described. Numbers of true and false positives and negatives were extracted and used to calculate likelihood ratios (LRs).

RESULTS

Thirteen studies met the selection criteria. The majority were based on clinically ascertained samples. Pooled LRs and 95% confidence intervals (CIs) for tense (LR+) and sentence repetition (LR+ and LR-) were suggestive of presence (LR+) or absence (LR-) of LI. Wide CIs around the value of inconsistency I2 index reduced reliability of pooled values for sentence repetition. High between-study heterogeneity precluded pooling of LR values for tense (LR-) and nonword repetition (LR+ and LR-).

CONCLUSION

The limited evidence available suggests that the proposed markers may be at best suggestive of LI in English. Future research may refine existing marker tasks to increase their accuracy and test the most promising tasks in unselected samples of participants with and without LI.

Cluster reduction and compensatory lengthening in the acquisition of possessive -s

Previous research shows that two-year-olds' third person singular -s and plural -s are produced more accurately in utterance-final compared to utterance-medial position. However, only the third person singular is affected by coda complexity. This study explores these effects with possessive -s. Acoustic analysis of twelve two-year-olds' elicited imitations examined the use of simple versus complex codas (e.g. Sue's vs. Doug's ) both utterance-medially and utterance-finally. Morpheme production was surprisingly robust across contexts, though coda clusters were often simplified to a lengthened -s morpheme utterance-medially (e.g., Dou's [dɐz]). The findings raise many questions about the development of speech planning processes across populations.

The role of utterance length and position in 3-year-olds' production of third person singular -s

PURPOSE Evidence from children's spontaneous speech suggests that utterance length and utterance position may help explain why children omit grammatical morphemes in some contexts but not others. This study investigated whether increased utterance length (hence, increased grammatical complexity) adversely affects children's third person singular -s production in more controlled experimental conditions. METHOD An elicited imitation task with 12 Australian English-speaking children ages 2;9 (years;months) to 3;2 (Mage = 2;11) was conducted comparing third person singular -s production in 3-word and 5-word utterances, both utterance medially (e.g., He sits back; He sits back and swings) and utterance finally (e.g., There he sits; That's the way he sits) using a within-subjects design. Children were shown pictorial representations of each utterance on a computer and were invited to repeat 16 pseudorandomized prerecorded utterances. Acoustic analysis determined the presence/absence and duration of the third person singular morpheme. RESULTS Third person singular production was significantly lower utterance medially compared to utterance finally for the 5-word utterances and significantly lower utterance medially in the 5-word compared to 3-word utterances. CONCLUSION These results suggest that increased utterance length results in significantly lower third person singular production, but only in the more articulatorily challenging utterance-medial position. Thus, morpheme omission is greatest at the intersection of grammatical and phonological complexity.

Grammatical outcomes of 3- and 6-year-old children who are hard of hearing

PURPOSE

Spoken language skills of 3- and 6-year-old children who are hard of hearing (HH) were compared with those of children with normal hearing (NH).

METHOD

Language skills were measured via mean length of utterance in words (MLUw) and percent correct use of finite verb morphology in obligatory contexts based on spontaneous conversational samples gathered from 185 children (145 HH, 40 NH). Aided speech intelligibility index (SII), better-ear pure-tone average (BE-PTA), maternal education, and age of amplification were used to predict outcomes within the HH group.

RESULTS

On average, the HH group had MLUws that were 0.25-0.5 words shorter than the NH group at both ages, and they produced fewer obligatory verb morphemes. After age, aided SII and age of amplification predicted MLUw. Aided SII and BE-PTA were not interchangeable in this analysis. Age followed by either BE-PTA or aided SII best predicted verb morphology use.

CONCLUSIONS

Children who are HH lag behind their peers with NH in grammatical aspects of language. Although some children appear to catch up, more than half of the children who are HH fell below the 25th percentile. Continued monitoring of language outcomes is warranted considering that children who are HH are at increased risk for language learning difficulties.

Acoustic investigations into the later acquisition of syllabic -es plurals

PURPOSE

Children acquire /-z/ syllabic plurals (e.g., bus es) later than /-s, -z/ segmental plurals (e.g., cat s, dog s). In this study, the authors explored whether increased syllable number or segmental factors best explains poorer performance with syllabic plurals.

METHOD

An elicited imitation experiment was conducted with 14 two-year-olds involving 8 familiar disyllabic target plural nouns, half with syllabic plurals (e.g., bus → bus es) and half with segmental plurals (e.g., letter → letter s). Children saw pictures of the target items on a computer and repeated prerecorded 3-word-utterances with the target word in utterance-medial position (e.g., "The buses come") and utterance-final position (e.g., "Hear the buses"). Acoustic analysis determined the presence or absence of the plural morpheme and its duration.

RESULTS

Children had more trouble producing syllabic plurals compared with segmental plurals. Errors were especially evident in the utterance-medial position, where there was less time for the child to perceive/produce the word in the absence of phrase-final lengthening and where planning for the following word was still required.

CONCLUSIONS

The results suggested that articulatory difficulties-rather than a word length effect-explain later acquisition of syllabic plurals relative to segmental plurals. These findings have implications for the nature of syllabic plural acquisition in children with hearing impairments and specific language impairment.

Durational cues to fricative codas in 2-year-olds' American English: voicing and morphemic factors

In the process of phonological development, fricatives are generally assumed to be later acquired than stops. However, most of the observational work on which this claim is based has concerned itself with word-initial onset consonants; little is known about how and when fricatives are mastered in word-final coda position (e.g., nose). This is all the more critical in a language like English, where word-final fricatives often carry important morphological information (e.g., toes, goes). This study examines the development of duration cues to the voicing feature contrast in coda fricatives, using longitudinal spontaneous speech data from CVC words (e.g., noise vs face) produced by three children (1;6-2;6 years) and six mothers. Results show that the children were remarkably adult-like in the use of duration cues to voicing contrasts in fricatives even in this early age range. Furthermore the children, like the mothers, had longer frication noise durations for morphemic compared to non-morphemic fricatives (e.g., toes vs nose) when these segments occurred in utterance-final position. These results suggest that although children's fricatives tend to be overall longer and more voiced compared to those of adults, the voicing and morphological contrasts for fricative codas are acquired early in production.

Acquisition of Turkish grammatical morphology by children with developmental disorders

BACKGROUND

Many children with specific language impairment, Down syndrome or autism spectrum disorder have difficulty learning grammatical morphology, especially forms associated with the verb phrase. However, except for Hebrew, the evidence thus far has come from Indo-European languages.

AIMS

This study investigates the acquisition of grammatical morphology by Turkish-speaking children with developmental disorders. Syntactic, perceptual and usage features of this non-Indo-European language were predicted to lead to patterns of atypical learning that would challenge and broaden current views.

METHODS & PROCEDURES

Language samples were collected from 30 preschoolers learning Turkish: ten with developmental disorders, ten matched by age and ten by length of utterance. T-SALT then generated mean length of utterance, the total number of noun errors, the total number of verb errors and the per cent use in obligatory contexts for noun suffixes. Analyses also looked at the potential effects of input frequency on order of acquisition.

OUTCOMES & RESULTS

Turkish children in the MLU-W control group, aged 3;4, used noun and verb suffixes with virtually no errors. Children in the group with atypical language showed more, and more persistent, morphological errors than either age or language peers, especially on noun suffixes. Children in the ALD and MLU-W groups were acquiring noun case suffixes in an order that is strongly related to input frequencies.

CONCLUSIONS & IMPLICATIONS

These findings seem to reflect the influence of salience, regularity and frequency on language learning. Typical child-adult discourse patterns as well as the canonical SOV Turkish word order make verb suffixes perceptually salient, available in working memory and frequently repeated. The findings support the view that the language patterns seen in children with atypical development will differ from one language type to the next. They also suggest that regardless of language or syntactic class, children will have greater difficulty with those features of grammar that have higher cognitive processing costs.

The Role of Phonology in Children's Acquisition of the Plural

The correct use of an affix, such as the English plural suffix, may reflect mastery of a morphological process but it may also depend on children's syntactic, semantic and phonological abilities. The present paper reports a set of experiments in support of this latter view, specifically focusing on the importance of the phonological make-up of plural forms for both production and comprehension. In Experiments 1 and 2 plural productions were elicited from eighty two-year-old children for nouns with codas with varying phonological properties. The results provide evidence that production of the plural morpheme is partly governed by the complexity of the coda and its sonority. Experiments 3 and 4 show that these constraints on codas also hold for comprehension as well, suggesting this effect is not simply articulatory, but also impacts the morphophonology of the plural.

Acoustic evidence for positional and complexity effects on children's production of plural -s

PURPOSE

Some variability in children's early productions of grammatical morphemes reflects phonological factors. For example, production of 3rd person singular -s is increased in utterance-final versus utterance-medial position and in simple versus cluster codas (e.g., sees vs. hits). Understanding the factors that govern such variability is an important step toward modeling developmental processes. In this study, the authors examined the generality of these effects by determining whether position and coda complexity influence production of plural -s, which phonologically manifests the same as 3rd person singular -s.

METHOD

The authors used an elicited imitation task to examine the speech of 16 two-year-olds. Eight plural nouns (half contained simple codas, half contained cluster codas) were elicited utterance-medially and utterance-finally. Acoustic analysis of each noun was used to identify acoustic cues associated with coda production.

RESULTS

Results showed that plural production was more robust in utterance-final versus utterance-medial position but equally robust in simple versus cluster codas.

CONCLUSIONS

These findings extend positional effects on morpheme production to plural -s. An effect of coda complexity was not observed for plural but was observed for 3rd person singular, which raises the possibility that the morphological representation proper influences the degree to which phonological factors affect morpheme production.

Sentence-position effects on children's perception and production of English third person singular -s

PURPOSE

Two-year-olds produce third person singular -s more accurately on verbs in sentence-final position as compared with verbs in sentence-medial position. This study was designed to determine whether these sentence-position effects can be explained by perceptual factors.

METHOD

For this purpose, the authors compared 22- and 27-month-olds' perception and elicited production of third person singular -s in sentence-medial versus-final position. The authors assessed perception by measuring looking/listening times to a 1-screen display of a cartoon paired with a grammatical versus an ungrammatical sentence (e.g., She eats now vs. She eat now).

RESULTS

Children at both ages demonstrated sensitivity to the presence/absence of this inflectional morpheme in sentence-final, but not sentence-medial, position. Children were also more accurate at producing third person singular -s sentence finally, and production accuracy was predicted by vocabulary measures as well as by performance on the perception task.

CONCLUSIONS

These results indicate that children's more accurate production of third person singular -s in sentence-final position cannot be explained by articulatory factors alone but that perceptual factors play an important role in accounting for early patterns of production. The findings also indicate that perception and production of inflectional morphemes may be more closely related than previously thought.

Interactions between lexical and phonological development: cross-linguistic and contextual considerations--a commentary on Stoel-Gammon's 'Relationships between lexical and phonological development in young children'

Stoel-Gammon (this issue) provides a welcome addition to the phonological acquisition literature, bringing together insights from long-standing and more recent research to address the relationship between the developing phonological system and the developing lexicon. A growing literature on children's early use of words across languages and phonological contexts provides additional insight into the nature of the interactions between phonological and lexical development, suggesting that learners' knowledge and connection of the two may develop much earlier than often thought. This commentary highlights some of these exciting results from recent cross-linguistic research on development between the ages of 1 and 3.

Phonological constraints on children's production of English third person singular -s

PURPOSE

Children variably produce grammatical morphemes at early stages of development, often omitting inflectional morphemes in obligatory contexts. This has typically been attributed to immature syntactic or semantic representations. In this study, the authors investigated the hypothesis that children's variable production of the 3rd person singular morpheme -s interacts with the phonological complexity of the verb stem to which it is attached.

METHOD

To explore this possibility, the authors examined longitudinal data from the spontaneous speech of 6 English-speaking children between ages 1;3 and 3;6 (years;months) and elicited imitations from a cross-sectional study of 23 two-year-olds (mean age of 2;2).

RESULTS

The results showed that children produced third person singular morphemes more accurately in phonologically simple coda contexts (e.g., sees) as compared with complex coda contexts (e.g., needs). In addition, children produced -s more accurately in utterance-final position as compared with utterance-medial position.

CONCLUSIONS

The results provide strong support for the role of phonological complexity in explaining some of the variability in children's production of third person singular -s. This finding suggests that future research will need to consider multiple factors, including phonological and positional effects, in constructing a comprehensive developmental theory of both grammatical competence and processes of speech planning and production.

Factors accounting for the ability of children with SLI to learn agreement morphemes in intervention

The aim of this study was to uncover factors accounting for the ability of children with specific language impairment (SLI) to learn agreement morphemes in intervention. Twenty-five children with SLI who participated in a six-month intervention program focused on teaching third person singular -s or auxiliary is/are/was showed a wide range of use of the target morpheme after intervention. Regression analyses showed that age and two factors expected to be related to agreement--the use of noun plural -s and subject/verb constructions prior to intervention--significantly predicted progress in the acquisition of agreement morphemes. In contrast, the pretreatment use of morphemes hypothesized to be unrelated to agreement was not a significant predictor of progress. The results indicate that the ability of children with SLI to learn agreement morphemes relies on their prior ability to use noun plural and subject/verb constructions.

A comparison of linguistic profiles in subgroups of children with specific language impairment

PURPOSE

To compare morphosyntactic skills of preschoolers in different subgroups of language impairment.

METHOD

Eighty-three children participated in this study. They represented 4 groups: (a) language impairment-only, (b) speech-language impairment with minimal or no final cluster reduction/consonant deletion, (c) speech-language impairment with frequent final cluster reduction/consonant deletion, and (d) a no-impairment control group. Group performance was compared for finite and nonfinite morpheme production and sentence structure.

RESULTS

Children in the language impairment-only group had significantly higher performance than children in both speech-language impairment subgroups, even when errors that could be attributed to final consonant deletion/cluster reduction were taken into account. The language impairment-only and control groups' performance was similar for finite and nonfinite morpheme production, and both groups produced nonfinite plurals with significantly higher accuracy than finite third person singular forms. The language impairment-only group had significantly higher accuracy for both plural and third person singular relative to the group with speech-language impairment characterized by infrequent final cluster reduction/consonant deletion.

CONCLUSIONS

Children with speech-language impairment generally had poorer morphosyntactic skills than peers who had language deficits and age-appropriate speech skills. Final consonant and final cluster production skills alone did not account for group differences. Clinically, the findings suggest that it is important to assess carefully the speech skills, including final cluster production skills, of preschoolers who have language deficits and language skills of preschoolers who have speech sound disorders.

Effects of acoustic manipulation on the real-time inflectional processing of children with specific language impairment

PURPOSE

This study reports the findings of an investigation designed to examine the effects of acoustic enhancement on the processing of low-phonetic-substance inflections (e.g., 3rd-person singular -s, possessive -s) versus a high-phonetic-substance inflection (e.g., present progressive -ing) by children with specific language impairment (SLI) in a word recognition, reaction time (RT) processing task. The effects of acoustic enhancement on the processing of the same morphemes as well as an additional morpheme (comparative -er) were examined in an offline grammaticality judgment task. The grammatical function of 1 of the higher-phonetic-substance inflections, -ing, was presumed to be hypothesized relatively early by children; the function of the other, -er, was presumed to be hypothesized relatively late.

METHOD

Sixteen children with SLI (age(M) = 9 years;0 months) and 16 chronological age (CA; age(M) = 8;11) children participated. For both tasks, children listened to sentences containing the target morphemes as they were produced naturally (natural condition) or with acoustic enhancement (enhanced condition).

RESULTS

On the RT task, the children with SLI demonstrated RT sensitivity only to the presence of the high-substance inflection, irrespective of whether it was produced naturally or with enhancement. Acoustic enhancement had no effect on these children's processing of low-substance inflections. The CA children, by contrast, showed sensitivity to low-substance inflections when they were produced naturally and with acoustic enhancement. These children also showed sensitivity to the high-substance inflection in the natural condition, but in the enhanced condition they demonstrated significantly slower RT. On the grammaticality judgment task, the children with SLI performed worse than the CA children overall and showed especially poor performance on low-substance inflections. Acoustic enhancement had a beneficial effect on the inflectional processing of the children with SLI, but it had no effect on CA children.

CONCLUSION

The findings are interpreted to suggest that the reduced language processing capacity of children with SLI constrains their ability to process low-substance grammatical material in real time. This factor should be considered along with any difficulty that might be attributable to the grammatical function of the inflection.

The role of salience in the extraction of algebraic rules

Recent research suggests that humans and other animals have sophisticated abilities to extract both statistical dependencies and rule-based regularities from sequences. Most of this research stresses the flexibility and generality of such processes. Here the authors take up an equally important project, namely, to explore the limits of such processes. As a case study for rule-based generalizations, the authors demonstrate that only repetition-based structures with repetitions at the edges of sequences (e.g., ABCDEFF but not ABCDDEF) can be reliably generalized, although token repetitions can easily be discriminated at both sequence edges and middles. This finding suggests limits on rule-based sequence learning and new interpretations of earlier work alleging rule learning in infants. Rather than implementing a computerlike, formal process that operates over all patterns equally well, rule-based learning may be a highly constrained and piecemeal process driven by perceptual primitives--specialized type operations that are highly sensitive to perceptual factors.

Ten principles of grammar facilitation for children with specific language impairments

Although they often have significant difficulties in other areas, most children with specific language impairment (SLI) have special difficulties with the understanding and use of grammar. Therefore, most of these children will require an intervention program that targets comprehension or production of grammatical form. Language interventionists are faced with the difficult task of developing comprehensive intervention programs that address the children's grammatical deficits while remaining sensitive to their other existing and predictable social, behavioral, and academic problems. The purpose of this article is to present and justify 10 principles that we regard as essential for planning adequate interventions for children with language-learning problems. These principles are relevant for all children with problems in the use of grammar, but they are especially appropriate for 3- to 8-year-old children with SLI. Although all of our examples are from English, the principles we have chosen are sufficiently broad to cut across many linguistic and cultural boundaries.

Verb and noun morphology in the spoken and written language of children with language learning disabilities

The purpose of this study was to investigate the use of verb and noun morphology in school-age children's spoken and written language. Sixty children, with and without language learning disabilities (LLD), each produced 2 spoken and 2 written language samples. The children's accuracy in using morphemes that mark verb finiteness (regular past tense, 3rd person singular present tense, copula, and auxiliary BE) was compared with their accuracy in using noun morphology (regular plural, possessive, articles). As would be expected, the typically achieving children, who were aged 7 to 12 years, had mastered the verb and noun morphology in spoken and written samples. The children with LLD, aged 10 to 12 years, also showed high accuracy in the spoken samples. On the other hand, they showed substantial difficulty in the written samples with the regular past tense, with errors in 26% of obligatory contexts. However, the children with LLD also had difficulty with the regular plural, with errors in 12% of obligatory contexts. For both the regular past tense and plural, all errors were errors of omission. These results indicate that finiteness marking remains an area of relative difficulty, but perhaps not the only grammatical difficulty, for children with language impairments in the school years.