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

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, 6 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.National Institutes of Health DC00433, RR7031K, DC00076, DC001694 (PI: Gierut)This is an Accepted Manuscript of an article published by Taylor & Francis in Clinical Linguistics & Phonetics on September 2013, available online: http://wwww.tandfonline.com/10.3109/02699206.2013.789928

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

This is the author's accepted manuscript. The original publication is available at http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8259251&fileId=S0305000910000176The 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

An on-line calculator to compute phonotactic probability and neighborhood density based on child corpora of spoken American English

This is the author's accepted manuscript. The original publication is available at http://link.springer.com/article/10.3758%2FBRM.42.2.497An on-line calculator was developed (http://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, based on child corpora of American English (Kolson, 1960; Moe, Hopkins, & Rush, 1982) and compared to 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. 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 high probability words; and child neighborhood density was lower than adult neighborhood density, especially for high density words. 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

Grammatical treatment and specific language impairment: Neighbourhood density & third person singular –s

This is the author's accepted manuscript. The original publication is available at http://www.tandfonline.com/doi/full/10.3109/02699206.2013.789928The 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, 6 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

Word learning by children with phonological delays: Differentiating effects of phonotactic probability and neighborhood density

This is the author's accepted manuscript. The original publication is available at http://www.sciencedirect.com/science/article/pii/S0021992409000847This 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

Using Nonword Repetition in Vocabulary Assessment

This is the author's accepted manuscript. The original is available at http://www.speechpathologyaustralia.org.au/publications/jcpslpStandardized vocabulary tests have been criticized for their cultural/experiential biases and insensitivity to word learning differences. This review discusses the utility of supplementing the diagnostic process with a processing-based measure, such as a nonword repetition task. Nonword repetition tasks have been heralded as a more sensitive indicator of individual differences in vocabulary/word learning. Evidence on the relationship between vocabulary and nonword repetition is discussed along with a review of the currently available tests of nonword repetition. Suggestions for constructing a nonword repetition task specific to the needs of individual clinicians are offered

Whole-Word versus Part-Word Phonotactic Probability/Neighborhood Density in Word Learning by Children

This is the published version

The Interface between the Lexicon and Finiteness Marking in Specific Language Impairment

Inconsistent omission of finiteness markers is a clinical marker for Specific Language Impairment (SLI). A similar pattern of omission is observed during normal development. Potential limiting factors during this stage of variability are not well understood. This research considered lexical representations, indexed by neighborhood density, as one limiting factor. Study 1 examined the effect of density on variable production of a finiteness marker by 4- and 5-year olds with SLI and by typically developing 3-year olds. The results showed that density was a limiting factor for typically developing children, but not for children with SLI. Study 2 examined the effect of density on finiteness growth in a learning task by children with SLI. Results showed differences in growth for children exposed to dense and sparse verbs. The combined results suggest that lexical representations interact with finiteness to differentially impact production and growth. Differences in density effects across groups are discussed

Differentiating the effects of phonotactic probability and neighborhood density on vocabulary comprehension and production: A comparison of preschool children with versus without phonological delays

This is the author's accepted manuscript. The original publication is available at http://jslhr.pubs.asha.org/article.aspx?articleid=1781591Purpose The purpose of this study was to differentiate the effect of phonotactic probability from that of neighborhood density on a vocabulary probe administered to preschool children with or without a phonological delay. Method Twenty preschool children with functional phonological delays and 34 preschool children with typical language development completed a 121 item vocabulary probe in both an expressive and receptive response format. Words on the vocabulary probe orthogonally varied on phonotactic probability and neighborhood density but were matched on age-of-acquisition, word frequency, word length, semantic set size, concreteness, familiarity, and imagability. Results Results showed an interaction between phonotactic probability and neighborhood density with variation across groups. Specifically, the optimal conditions for typically developing children were rare phonotactic probability with sparse neighborhoods and common phonotactic probability with dense neighborhoods. In contrast, only rare phonotactic probability with sparse neighborhoods was optimal for children with phonological delays. Conclusions Rare sound sequences and sparse neighborhoods may facilitate triggering of word learning for typically developing children and children with phonological delays. In contrast, common sound sequences and dense neighborhoods may facilitate configuration and engagement for typically developing children but not children with phonological delays due to their weaker phonological and/or lexical representations

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, 20 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. Children's 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.National Institutes of Health DC00433, RR7031K, DC00076, DC001694 (PI: Gierut