Why do infants learn some words earlier than others? Many theories of early word learning focus on explaining how infants map labels onto concrete objects. However, words that are more abstract than object nouns, such as "uh-oh," "hi," "more," "up," and "all-gone," are typically among the first to…

Using a habituation paradigm with a three-switch design, the present study investigated whether 20-month-old French-learning infants use noun and verb morphosyntactic cues to learn novel words in dynamic events differentially when both the agent and the action interpretations are possible. Of particular interest was whether infants' initial…

We test the comprehension of transitive sentences in very young learners of Mandarin Chinese using a combination of the weird word order paradigm with the use of pseudo-verbs and the preferential looking paradigm, replicating the experiment of Franck et al. (2013) on French. Seventeen typically-developing Mandarin infants (mean age: 17.4 months)…

This study investigates the influence of semantic maturation on early lexical development by examining the impact of contextual diversity--known to influence semantic development--on word promotion from receptive to productive vocabularies (i.e., comprehension-expression gap). Study 1 compares the vocabularies of 3685 American-English-speaking…

Previous studies show that infants store functional morphemes for inferring syntactic categories of adjacent words, and they generally perform better with nouns than with verbs. In this study, we tested whether toddlers can exploit phrasal groupings for syntactic categorization in the face of noisy co-occurrence patterns. Using a visual fixation…

Previous research has highlighted the difficulty that infants have in learning to use color words. Even after acquiring the words themselves, infants are reported to use them incorrectly, or overextend their usage. We tested 146 infants from 5 different age groups on their knowledge of 6 basic color words, "red", "green",…

This research brings new evidence on early lexical acquisition in Wichi, an under-studied indigenous language in which verbs occupy a privileged position in the input and in conjunction with nouns are characterized by a complex and rich morphology. Focusing on infants ranging from one- to three-year-olds, we analyzed the parental report of…

Measurements of infants' quotidian experiences provide critical information about early development. However, the role of sampling methods in providing these measurements is rarely examined. Here we directly compare language input from hour-long video-recordings and daylong audio-recordings within the same group of 44 infants at 6 and 7 months. We…

This study examines the quantity and quality of child-directed speech across household activities in a socioeconomically diverse sample of Argentinian Spanish-speaking children, an understudied population. Thirty children (mean: 14.3 months) and their families were audio-recorded for four hours. The middle two hours were transcribed and analysed…

Previous research indicates that infant-directed speech (IDS) is usually slower than adult-directed speech (ADS) and mothers prefer placing a focused word in isolation or utterance-final position in (English) IDS, which may benefit word learning. This study investigated the speaking rate and word position of IDS in two typologically-distinct…

English-learning infants attend to lexical stress when learning new words. Attention to lexical stress might be beneficial for word learning by providing an indication of the grammatical class of that word. English disyllabic nouns commonly have trochaic (strong-weak) stress, whereas English disyllabic verbs commonly have iambic (weak-strong)…

The syntactic structure of sentences in which a new word appears may provide listeners with cues to that new word's form class. In English, for example, a noun tends to follow a determiner ("a"/"an"/"the"), while a verb precedes the morphological inflection [ing]. The presence of these markers may assist children in…

In infancy, maternal socioeconomic status (SES) is associated with real-time language processing skills, but whether or not (and if so, how) this relationship carries into adulthood is unknown. We explored the effects of maternal SES in college-aged adults on eye-tracked, spoken sentence comprehension tasks using the visual world paradigm. When…

We assessed 24-month-old infants' lexical processing efficiency for both novel and familiar words. Prior work documented that 19-month-olds successfully identify referents of familiar words (e.g., The dog is so little) as well as novel words whose meanings were informed only by the surrounding sentence (e.g., The vep is crying), but that the speed…

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…