a b s t r a c t During the past ten years, research using Near-infrared Spectroscopy (NIRS) to study the developing brain has provided groundbreaking evidence of brain functions in infants. This paper presents a theoretically oriented review of this wealth of evidence, summarizing recent NIRS data on language processing, without neglecting other neuroimaging or behavioral studies in infancy and adulthood. We review three competing classes of hypotheses (i.e. signal-driven, domain-driven, and learning biases hypotheses) regarding the causes of hemispheric specialization for speech processing. We assess the fit between each of these hypotheses and neuroimaging evidence in speech perception and show that none of the three hypotheses can account for the entire set of observations on its own. However, we argue that they provide a good fit when combined within a developmental perspective. According to our proposed scenario, lateralization for language emerges out of the interaction between pre-existing left-right biases in generic auditory processing (signaldriven hypothesis), and a left-hemisphere predominance of particular learning mechanisms (learning-biases hypothesis). As a result of this completed developmental process, the native language is represented in the left hemisphere predominantly. The integrated scenario enables to link infant and adult data, and points to many empirical avenues that need to be explored more systematically.

An important distinction between phonology and syntax has been overlooked. All phonological patterns belong to the regular region of the Chomsky Hierarchy but not all syntactic patterns do. We argue that the hypothesis that humans employ distinct learning mechanisms for phonology and syntax currently offers the best explanation for this difference. 1 A role for phonology in cognitive science Whenitcomestotheproblemofhowhumanslearnlanguage, itappearsmanycomputational learning theorists, cognitive scientists, and psychologists are primarily occupied with the problem of how humans learn to put words and morphemes together to form sentences. In this article we argue that a further understanding of how sounds are put together to form words also bears directly on fundamental questions in cognitive science. In particular, we argue that computational analysis of the typology of patterns in phonology, when compared to the typology of patterns in syntax, reveals that cognitive learning mechanisms are likely multiple and modular in nature. The skew that many researchers exhibit towards morpho-syntax may really be a skew towards studying meaning. But we believe that it is because phonological systems impose different sound patterns in different languages without contributing to meaning that they are especially interesting. That is, phonology is about “Rules without Meaning ” in Frits Staal’s (1989) terms. We also believe that an apparent lack of teleological purpose in phonology is what lessens its appeal to the outside. A good discussion of the strangeness of studying phonology is provided inKaye (1989)where he considers what a programming languagelike BASIC would The authors thank Jim Rogers for valuable discussion and an anonymous reviewer and Nick Chater for

This paper provides a computational analysis of 39 attested vowel harmony patterns in a recent typological analysis (Nevins, 2010), in addition to two unattested harmony patterns which have attracted considerable discussion: ‘majority rules ’ (Lombardi, 1999; Baković, 2000) and ‘sour grapes ’ (Padgett, 1995). It is shown that these attested patterns, unlike the two unattested ones, are subsequential. We

This paper demonstrates the role of morphological alternations in learning novel phonotactic patterns. In an artificial grammar learning task, adult learners were exposed to a phonotactic pattern in which the first and last consonant agreed in voicing. Long-distance phonotactics encoded as strictly piecewise languages suggest that first-last phonotactic patterns should be unattested in natural language. However, recent theories of morphologically induced phonological patterns predict that long-distance agreement between the first and last consonant of a word can occur when the agreement is induced as a morphological alternation. The results of two experiments support the prediction that first-last harmony patterns are more easily learned when morphological cues to the pattern are present. Participants only learned the first-last pattern when presented as a morphological alternation.