Jill R. Hoover

An online calculator to compute phonotactic probability and neighborhood density on the basis of child corpora of spoken American English.

An online calculator was developed (www.bncdnet.ku.edu/cml/info_ccc.vi) to compute phonotactic probability—the likelihood of occurrence of a sound sequence—and neighborhood density—the number of phonologically similar words—on the basis of child corpora of American English (Kolson, 1960; Moe, Hopkins, & Rush, 1982) and to compare its results to those of an adult calculator. Phonotactic probability and neighborhood density were computed for a set of 380 nouns (Fenson et al., 1993) using both the child and adult corpora. The child and adult raw values were significantly correlated. However, significant differences were detected. Specifically, child phonotactic probability was higher than adult phonotactic probability, especially for highprobability words, and child neighborhood density was lower than adult neighborhood density, especially for words with high-density neighborhoods. These differences were reduced or eliminated when relative measures (i.e., z scores) were used. Suggestions are offered regarding which values to use in future research.

Word Learning by Children with Phonological Delays: Differentiating Effects of Phonotactic Probability and Neighborhood Density.

UNLABELLED This study examined the ability of 20 preschool children with functional phonological delays and 34 age- and vocabulary-matched typical children to learn words differing in phonotactic probability (i.e., the likelihood of occurrence of a sound sequence) and neighborhood density (i.e., the number of words that differ from a target by one phoneme). Children were exposed to nonwords paired with novel objects in a story and learning was measured by a picture naming task. Results showed that both groups created lexical representations for rare sound sequences from sparse neighborhoods. However, only children with typical development appeared to build on this initial lexical representation to create a full representation of the word (i.e., lexical-semantic connection and semantic representation). It was hypothesized that creating a lexical representation may be too resource demanding for children with phonological delays, leaving few resources available to create a lexical-semantic connection and/or a semantic representation. LEARNING OUTCOMES The reader will be able to (1) define phonotactic probability; (2) define neighborhood density; (3) identify how these variables impact the word learning process in general; (4) identify potential areas of deficit in the word learning process for children with functional phonological delays.

The Interface between Neighborhood Density and Optional Infinitives: Normal Development and Specific Language Impairment.

The effect of neighborhood density on optional infinitives was evaluated for typically developing (TD) children and children with Specific Language Impairment (SLI). Forty children, twenty in each group, completed two production tasks that assessed third person singular production. Half of the sentences in each task presented a dense verb, and half presented a sparse verb. Childrens third person singular accuracy was compared across dense and sparse verbs. Results showed that the TD group was significantly less likely to use optional infinitives with dense, rather than sparse verbs. In contrast, the distribution of optional infinitives for the SLI group was independent of verb neighborhood density. Follow-up analyses showed that the lack of neighborhood density effect for the SLI group could not be attributed to heterogeneous neighborhood density effects or floor effects. Results were interpreted within the Optional Infinitive/Extended Optional Infinitive accounts for typical language development and SLI for English-speaking children.

The influence of part-word phonotactic probability/neighborhood density on word learning by preschool children varying in expressive vocabulary

The goal of this study was to examine the influence of part-word phonotactic probability/neighborhood density on word learning by preschool children with normal vocabularies that varied in size. Ninety-eight children (age 2 ; 11-6 ; 0) were taught consonant-vowel-consonant (CVC) nonwords orthogonally varying in the probability/density of the CV (i.e. body) and VC (i.e. rhyme). Learning was measured via picture naming. Children with the lowest expressive vocabulary scores showed no effect of either CV or VC probability/density, although floor effects could not be ruled out. In contrast, children with low or high expressive vocabulary scores demonstrated sensitivity to part-word probability/density with the nature of the effect varying by group. Children with the highest expressive vocabulary scores displayed yet a third pattern of part-word probability/density effects. Taken together, word learning by preschool children was influenced by part-word probability/density but the nature of this influence appeared to depend on the size of the lexicon.

Grammatical treatment and specific language impairment: neighbourhood density & third person singular -s.

Abstract The purpose of this study was to test the effect of manipulating verb neighbourhood density in treatment targeting the third person singular lexical affix. Using a single-subject experimental design, six pre-schoolers with Specific Language Impairment (SLI) were randomly assigned to one of two conditions: (1) treatment with sparse verbs or (2) treatment with dense verbs in 12 sessions. The third person singular lexical affix was targeted for 12 sessions of treatment in both conditions. Treatment gain and generalization were measured as the dependent variables. Third person singular % correct change from pre-treatment to post-treatment was measured using sentence production tasks with comparisons across the two treatment conditions. Treatment gain and generalization were greater for children enrolled in the sparse condition. Preliminary clinical recommendations are made and theoretical implications are discussed relative to neighbourhood density effects on lexical activation and storage in children with SLI.

Examining the Language Phenotype in Children with Typical Development, Specific Language Impairment, and Fragile X Syndrome.

Purpose One aspect of morphosyntax, finiteness marking, was compared in children with fragile X syndrome (FXS), specific language impairment (SLI), and typical development matched on mean length of utterance (MLU). Method Nineteen children with typical development (mean age = 3.3 years), 20 children with SLI (mean age = 4.9 years), and 17 boys with FXS (mean age = 11.9 years) completed the Test of Early Grammatical Impairment (TEGI; Rice & Wexler, 2001), and other cognitive and language assessments. Quantitative comparisons on finiteness marking and qualitative comparisons of unscorable (i.e., nontarget) TEGI responses were conducted. Results Children with typical development and FXS performed better on finiteness marking than children with SLI. Although unscorable responses were infrequent, boys with FXS produced more unscorable responses than children with typical development and SLI. Conclusions Although boys with FXS have language deficits, they performed similarly to MLU-matched typically developing children on finiteness marking. This language profile differs from children with SLI, who present with a delay-within-a-delay profile with finiteness marking delays that exceed delays in MLU. Unscorable responses produced by the boys with FXS may reflect pragmatic deficits, which are prominent in this population. Assessment procedures should be carefully considered when examining language in boys with FXS.

Representations involved in short‐term versus long‐term word learning by preschool children with and without phonological disorders

This study explores whether sublexical (i.e., individual sound) and/or lexical (i.e., whole‐word) representations contribute to word learning and whether these contributions change across short‐term versus long‐term learning. Sublexical representations were indexed by phonotactic probability, the likelihood of occurrence of a sound sequence, whereas lexical representations were indexed by neighborhood density, the number of similar sounding words. Thirty‐four preschool children participated in a short‐term word learning task that exposed them to nonwords varying in phonotactic probability and neighborhood density and tested learning of these nonwords. Long‐term learning was assessed through comprehension and production of real words varying in phonotactic probability and neighborhood density. Results showed that phonotactic probability and neighborhood density equally influenced short‐term word learning. In contrast, long‐term word learning was affected primarily by neighborhood density. Thus, both sublex...