Purpose: Our knowledge of speech rate development remains inadequate because of limited longitudinal data and lack of data from children under age 3;0 (years;months). The purpose of this longitudinal study was to test the pattern of speech rate development between ages 2;0 and 3;0. Method: Speech rate was assessed at 4 time points between ages 2;0…

Purpose: This tutorial is an introduction to first phase syntax (FPS; Ramchand, 2008). FPS provides a new, cross-linguistically motivated perspective on clause internal structure. A new sequence of syntactic development is proposed based on FPS with 4 levels of complexity: (0) verb particles and adjectives in the 1-word stage, (1) semantic…

Purpose: This article focuses on toddlers' revisions of the sentence subject and tests the hypothesis that subject diversity (i.e., the number of different subjects produced) increases the probability of subject revision. Method: One-hour language samples were collected from 61 children (32 girls) at 27 months. Spontaneously produced, active…

The purpose of this study was to determine if children acquire grammatical case as a unified system or in a piecemeal fashion. In English language acquisition, many children make developmental errors in marking case on subject position pronouns (e.g., "Me" do it, "Him" like it). It is unknown whether children who produce…

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…

This article investigates the relationship between third person singular present tense agreement morphemes, copula "is" and verb-"s", at 2;00 and 2;03. Language samples from 60 children at 2;00 were analyzed for the productivity of copula "is" as measured by the number of different morphemes preceding "is"…

The contribution of parent input to children's subsequent expressive verb diversity was explored in twenty typically developing toddlers with small verb lexicons. Child developmental factors and parent input measures (i.e. verb quantity, verb diversity, and verb-related structural cues) at age 1;9 were examined as potential predictors of…

Purpose: This follow-up study examined whether a parent intervention that increased the diversity of lexical noun phrase subjects in parent input and accelerated children's sentence diversity (Hadley et al., 2017) had indirect benefits on tense/agreement (T/A) morphemes in parent input and children's spontaneous speech. Method: Differences in…

Purpose: The goals of this study were to quantify longitudinal expectations for verb lexicon growth and to determine whether verb lexicon measures were better predictors of later grammatical outcomes than noun lexicon measures. Method: Longitudinal parent-report measures from the MacArthur-Bates Communicative Development Inventory (Fenson et al.,…

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…