Crosslinguistic word order variation reflects evolutionary pressures of dependency and information locality

Evidence for word order harmony between abstract categories in silent gesture

Cross-category harmony is the tendency for languages to use consistent orders of heads and dependents across different types of phrases. For example, languages tend to either place both verbs and adpositions before their dependents (e.g., 'seethe girl', 'tothe store' as in English) or after (e.g., 'the girlsee', 'the storeto' as in Turkish). Harmony has been argued to reflect a cognitive bias for simpler rules: a single high level abstract rule is simpler to learn than multiple rules, one for each type of head and dependent (Culbertson and Kirby, 2016). This has been supported by recent experimental work indicating that learners prefer to consistently order nouns either before or after different nominal modifiers (e.g. Culbertson et al., 2012, 2020a) and different types of verbs (Motamedi et al., 2022), and generalise the relative order of verb and noun to the order of an adposition and noun (Wang et al., in press). However, these studies all use the exact same set of nouns for both the training and testing stimuli. This leaves open the possibility that participants are noticing surface-level patterns, i.e., matching the position of specific nouns across phrases. This would give the appearance of a preference for cross-category harmony, but would not reflect anything about the alignment of categories, or a preference for fewer abstract rules. This paper describes three experiments that were designed to establish whether there is a cognitive bias for cross-category harmony between the adpositional phrase and the verb phrase which persists when the possibility of using surface-level patterns is removed.

A Simple Explanation for Harmonic Word Order

Harmonic word order is a well-established tendency in natural languages, which has previously been explained as a single ordering rule for all head-dependent relations. We propose that it can be more parsimoniously explained as an outcome of word-class frequencies, where the purported "head" is the most frequently instantiated word class in a phrasal schema. We show that the most frequent class gravitates spontaneously to an edge position in a phrasal replication process, as long as words of one class may influence the position of words of another class. This avoids the need to posit head-dependent ordering as an innate rule or bias, simplifying our theory of word order. We demonstrate the spontaneous emergence of harmony from word-class frequencies using a simple computational model of phrasal replication, and in further extensions show that the principle remains robust with fuzzy word classes and multiword chunks, can capture competition between harmony and locality, and is compatible with the results of behavioral experiments on harmonic ordering. Our findings support further exploration of syntactic models with nondiscrete word classes.

Language follows a distinct mode of extra-genomic evolution

As one of the most specific, yet most diverse of human behaviors, language is shaped by both genomic and extra-genomic evolution. Sharing methods and models between these modes of evolution has significantly advanced our understanding of language and inspired generalized theories of its evolution. Progress is hampered, however, by the fact that the extra-genomic evolution of languages, i.e. linguistic evolution, maps only partially to other forms of evolution. Contrasting it with the biological evolution of eukaryotes and the cultural evolution of technology as the best understood models, we show that linguistic evolution is special by yielding a stationary dynamic rather than stable solutions, and that this dynamic allows the use of language change for social differentiation while maintaining its global adaptiveness. Linguistic evolution furthermore differs from technological evolution by requiring vertical transmission, allowing the reconstruction of phylogenies; and it differs from eukaryotic biological evolution by foregoing a genotype vs phenotype distinction, allowing deliberate and biased change. Recognising these differences will improve our empirical tools and open new avenues for analyzing how linguistic, cultural, and biological evolution interacted with each other when language emerged in the hominin lineage. Importantly, our framework will help to cope with unprecedented scientific and ethical challenges that presently arise from how rapid cultural evolution impacts language, most urgently from interventional clinical tools for language disorders, potential epigenetic effects of technology on language, artificial intelligence and linguistic communicators, and global losses of linguistic diversity and identity. Beyond language, the distinctions made here allow identifying variation in other forms of biological and cultural evolution, developing new perspectives for empirical research.

Information distribution patterns in naturalistic dialogue differ across languages

The natural ecology of language is conversation, with individuals taking turns speaking to communicate in a back-and-forth fashion. Language in this context involves strings of words that a listener must process while simultaneously planning their own next utterance. It would thus be highly advantageous if language users distributed information within an utterance in a way that may facilitate this processing-planning dynamic. While some studies have investigated how information is distributed at the level of single words or clauses, or in written language, little is known about how information is distributed within spoken utterances produced during naturalistic conversation. It also is not known how information distribution patterns of spoken utterances may differ across languages. We used a set of matched corpora (CallHome) containing 898 telephone conversations conducted in six different languages (Arabic, English, German, Japanese, Mandarin, and Spanish), analyzing more than 58,000 utterances, to assess whether there is evidence of distinct patterns of information distributions at the utterance level, and whether these patterns are similar or differed across the languages. We found that English, Spanish, and Mandarin typically show a back-loaded distribution, with higher information (i.e., surprisal) in the last half of utterances compared with the first half, while Arabic, German, and Japanese showed front-loaded distributions, with higher information in the first half compared with the last half. Additional analyses suggest that these patterns may be related to word order and rate of noun and verb usage. We additionally found that back-loaded languages have longer turn transition times (i.e., time between speaker turns).

Language is primarily a tool for communication rather than thought

Language is a defining characteristic of our species, but the function, or functions, that it serves has been debated for centuries. Here we bring recent evidence from neuroscience and allied disciplines to argue that in modern humans, language is a tool for communication, contrary to a prominent view that we use language for thinking. We begin by introducing the brain network that supports linguistic ability in humans. We then review evidence for a double dissociation between language and thought, and discuss several properties of language that suggest that it is optimized for communication. We conclude that although the emergence of language has unquestionably transformed human culture, language does not appear to be a prerequisite for complex thought, including symbolic thought. Instead, language is a powerful tool for the transmission of cultural knowledge; it plausibly co-evolved with our thinking and reasoning capacities, and only reflects, rather than gives rise to, the signature sophistication of human cognition.

Icono: a universal language that shows what it says

This article lays out the foundation of a new language for easier written communication that is inherently reader-friendly and inherently international. Words usually consist of strings of sounds or squiggles whose meanings are merely a convention. In Icono, instead, they typically are strings of icons that illustrate what they stand for. "Train," for example, is expressed with the icon of a train, "future" with the icon of a clock surrounded by a clockwise arrow, and "mammal" with the icons of a cow and a mouse-their combination's meaning given by what they have in common. Moreover, Icono reveals sentence structure graphically before, rather than linguistically after, one begins reading. On smartphones and computers, writing icons can now be faster than writing alphabetic words. And using simple pictures as words helps those who struggle with conditions like dyslexia, aphasia, cerebral palsy, and autism with speech impairment. Because learning its pronunciation or phonetic spelling is optional rather than a prerequisite, and because it shows what it says, Icono is bound to be easier to learn to read-and then easier to read-than any other language, including our own.