Languages exhibit variation at all linguistic levels, from phonology, to the lexicon, to syntax. Importantly, that variation tends to be (at least partially) conditioned on some aspect of the social or linguistic context. When variation is unconditioned, language learners regularize it -- removing some or all variants, or conditioning variant use…

Using an oral sentence production task, we investigated how preschoolers (N = 28) produce agreement with complex noun phrases and compared their performance to college students (N = 32) to determine whether preschoolers produce agreement patterns that are qualitatively similar to adults'. We also conducted corpus analyses to investigate relevant…

The cross-categorical use of nouns and verbs poses a challenging problem to young language learners because they are known to be less willing to accept that a single form of a word be used for more than one linguistic purpose (e.g., one-form/one-function principle). The present study investigated whether children under 3 years of age are able to…

We present an artificial language experiment investigating (i) how speakers of languages such as English with two-way obligatory distinctions between singular and plural learn a system where singular and plural are only optionally marked, and (ii) how learners extend their knowledge of the plural morpheme when under the scope of negation without…

We tested 12- and 18-month-old English-learning infants on a preferential-looking task which contrasted grammatically correct sentences using the determiner "the" vs. three ungrammatical conditions in which "the" was substituted by another English function word, a nonsense word, or omitted. Our design involved strict controls…

By their second birthday, children have begun using grammatical cues to decipher the meaning of newly encountered words. By 3 years of age, there is evidence that children are more reliant on grammatical than social cues to decipher verb meaning (Nappa, Wessel, McEldoon, Gleitman, & Trueswell, 2009). Here, we investigate children's reliance on…

The phenomenon of regularization -- learners imposing systematicity on inconsistent variation in language input -- is complex. Studies show that children are more likely to regularize than adults, but adults will also regularize under certain circumstances. Exactly why we see the pattern of behaviour that we do is not well understood, however.…

The study investigated the influence of universal and language-specific morpho-syntactic properties (i.e., flexible word order, case) on the acquisition of verb argument structures in German compared with English. To this end, 65 three- to nine-year-old German learning children and adults were asked to act out grammatical ("The sheep…

Purpose: The current study used an intervention design to test the hypothesis that parent input sentences with diverse lexical noun phrase (NP) subjects would accelerate growth in children's sentence diversity. Method: Child growth in third person sentence diversity was modeled from 21-30 months (n = 38) in conversational language samples obtained…

In many languages, significant numbers of words are used in more than one grammatical category; English, in particular, has many words that can be used as both nouns and verbs. Such "ambicategoricality" potentially poses problems for children trying to learn the grammatical properties of words and has been used to argue against the logical…

Handshape works differently in nouns versus a class of verbs in American Sign Language (ASL) and thus can serve as a cue to distinguish between these two word classes. Handshapes representing characteristics of the object itself ("object" handshapes) and handshapes representing how the object is handled ("handling" handshapes)…