Human languages, signed and spoken, can be characterized by the structural patterns they use to associate communicative "forms" with "meanings." One such pattern is paradigmatic morphology, where complex words are built from the systematic use "and re-use" of sub-lexical units. Here, we provide evidence of emergent…

When linguistic input contains inconsistent use of grammatical forms, children produce these forms more consistently, a process called "regularization." Deaf children learning American Sign Language from parents who are non-native users of the language regularize their parents' inconsistent usages. In studies of artificial languages…

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…

English-speaking children use plural morphology from around the age of 2, yet often omit the syllabic plural allomorph /-[schwa]z/ until age 5 (e.g., "bus(es)"). It is not clear if this protracted acquisition is due to articulatory difficulties, low input frequency, or fricative-final words (e.g., "bus," "nose") being…

We examined French-learning toddlers' sensitivity to Subject-Verb agreement with conjoined subjects. In French, a conjoined NP triggers plural agreement even when made up of individual singular NPs. Processing of this infrequent structure in the input (see Corpus Analyses) requires going beyond surface patterns of non-adjacent dependencies to…

Beginning with the classic work of Shepard, Hovland, & Jenkins (1961), Type II visual patterns (e.g., exemplars are large white squares OR small black triangles) have held a special place in investigations of human learning. Recent research on Type II "linguistic" patterns has shown that they are relatively frequent across languages…

The Mandarin resultative verb compound (RVC; e.g., "tui dao" "push fall" and "pa shang" "climb ascend") encodes complex events composed of an initiating action and resulting activity or state. This study investigated when Mandarin-speaking children acquired this language-specific device. Specifically, we…

In a variety of domains, adults who are given input that is only partially consistent do not discard the inconsistent portion (regularize) but rather maintain the probability of consistent and inconsistent portions in their behavior (probability match). This research investigates the possibility that adults probability match, at least in part,…

In this paper we investigate the effect of variable input on the acquisition of grammar. More specifically, we examine the acquisition of the third person singular marker -s on the auxiliary "do" in comprehension and production in two groups of children who are exposed to similar varieties of English but that differ with respect to adult…