Judith A. Gierut

Phonological Treatment Efficacy and Developmental Norms

The efficacy of teaching sounds in developmental sequence as defined by age norms was evaluated in two independent investigations. Study I was a within-subject evaluation using an alternating treat...

Lexical constraints in phonological acquisition.

Lexical diffusion, as characterized by interword variation in production, was examined in phonological acquisition. The lexical variables of word frequency and neighbourhood density were hypothesized to facilitate sound change to varying degrees. Twelve children with functional phonological delays, aged 3;0 to 7;4, participated in an alternating treatments experiment to promote sound change. Independent variables were crossed to yield all logically possible combinations of high/low frequency and high/low density in treatment; the dependent measure was generalization accuracy in production. Results indicated word frequency was most facilitative in sound change, whereas, dense neighbourhood structure was least facilitative. The salience of frequency and avoidance of high density are discussed relative to the type of phonological change being induced in childrens grammars, either phonetic or phonemic, and to the nature of childrens representations. Results are further interpreted with reference to interactive models of language processing and optimality theoretic accounts of linguistic structure.

Phonemic structures of delayed phonological systems

The phonemic inventories of 30 children (aged 3;4-5;7) with phonological delays were examined in terms of featural distinctions in order to address universal vs. individual accounts of acquisition. Phonetic inventories of these same children were also identified for comparison purposes. Across children, four hierarchical and implicationally related types of phonemic inventory were identified. The typology uniquely captured common distinctions maintained by all children, and at the same time, allowed for individual differences in the specific phonemic composition of each system. These cross-sectional results have theoretical implications for the longitudinal course of phonemic acquisition. In particular, children appear to have a number of linguistic choices that relate to the course, the specifics, and the mechanism of change in acquisition.

On Word-Initial Voicing : Converging Sources of Evidence in Phonologically Disordered Speech

The purpose of this study is to bring related sources of data, i.e., phonological and acoustic phonetic, to bear on the characterization of two childrens disordered phonological systems. Auditorily-based phonological analyses indicated that the children exhibited a superficially similar pattern of error involving the voice contrast in word-initial obstruent stops, even though both children accurately produced the voice contrast in post-vocalic stops. Acoustic phonetic analyses indicated, however, that one of the children systematically effected the voice distinction using closure duration and voice onset time, whereas the other child did not. Despite the similarity of their errors as assessed by auditorily-based phonological analyses, the children had very different productive knowledge of word-initial voicing in stops. These findings have implications for the clinical assessment and treatment of children with phonological disorders.

The puzzle-puddle-pickle problem and the Duke-of-York gambit in acquisition

Two classic and previously unrelated problems are reconsidered for their implications for optimality theory and acquisition. The puzzle-puddle-pickle problem centers on the debate over children’s underlying representations and the characterization of interacting error patterns which, when lost, result in overgeneralizations. In response to the challenges that this problem poses, an optimality theoretic solution is offered that appeals to the second problem, the Duke-of-York gambit, which involves co-occurring generalizations with reverse effects. The solution avoids language-specific restrictions on input representations and characterizes the loss and introduction of errors by one mechanism. New insight is offered for when overgeneralization is (not) expected to occur.

Homonymy in phonological change

This study examines the role of homonymy as a motivator of phonological change in treatment. The relative effectiveness of two treatment structures in improving the production of treated and untreated error sounds was evaluated. One treatment structure emphasized homonymous forms by comparing 1:1 a desired ambient target with its corresponding replacement error from the childs grammar, consistent with conventional minimal pair treatment (Weiner, 1981). The other treatment did not focus on homonymy, nor did it make explicit reference to a childs grammar. In line with treatment of the empty or unknown set (Gierut, 1989), two errored sounds were simply compared with each other. Differential learning was observed among the treatments such that the non-homonymous structure resulted in greater accuracies of treated sounds and in more new untreated sounds being added to the phonological system. The findings have potential implications for the status of homonymy in phonological change and in the structure of phonological treatment.

Comparability of lexical corpora: word frequency in phonological generalization.

Statistical regularities in language have been examined for new insight to the language acquisition process. This line of study has aided theory advancement, but it also has raised methodological concerns about the applicability of corpora data to child populations. One issue is whether it is appropriate to extend the regularities observed in the speech of adults to developing linguistic systems. The purpose of this paper is to establish the comparability of lexical corpora in accounting for behavioural effects of word frequency on childrens phonological generalization. Four word frequency corpora were evaluated in comparison of child/adult and written/spoken sources. These were applied post‐hoc to generalization data previously reported for two preschool children. Results showed that the interpretation of phonological generalization was the same within and across children, regardless of the corpus being used. Phonological gains were more evident in low than high frequency words. The findings have implications for the design of probabilistic studies of language acquisition and clinical treatment programmes.

Precursors to onset clusters in acquisition

Two lawful relationships involving word-initial onset clusters have been advanced in the acquisition literature; namely, that clusters imply affricates (Lleó & Prinz, 1996, 1997), and that liquid clusters imply a liquid distinction (Archibald, 1998). This study evaluated and extended the validity of these implicational laws in a population of 110 children (aged 3;0 to 8;6) with functional phonological delays who contributed extended speech samples for computational analyses. Results indicated that, for the most part, the composition of childrens sound systems were in compliance with the proposed laws; however, there were noted asymmetries and apparent exceptions in the data. The asymmetries motivated an integration of the two laws to reveal a pattern of segmental-prosodic cyclicity consistent with deterministic models of phonological acquisition. The apparent exceptions highlighted the relevance of independent methodologies and offered a potential theoretical alternative with the Resolvability Principle as directions for future research.

Markedness and the grammar in lexical diffusion of fricatives

This paper examines the contributions of markedness and a childs grammar to the process of lexical diffusion in phonological acquisition. Archival data from 19 preschoolers with functional phonological delays were submitted to descriptive analyses of productive sound change in fricatives. Childrens presenting fricative inventory, the fricatives newly learned, and their position of occurrence were varied, with word frequency and neighbourhood density measured. Results indicated that lexical diffusion of fricatives occurred differentially by word position. Positional, featural and structural markedness further converged such that change in unmarked structure of any type was implemented in low frequency words. A childs presenting fricative inventory was not directly affiliated with systematic patterns of diffusion. These results have clinical applications for the evaluation of productive sound change and theoretical implications for deterministic models of lexical diffusion and processing models of word recognition.

Natural domains of cyclicity in phonological acquisition

This study expands and further validates cyclicity in the course of phonological development by exploring a potential relationship between the acquisition of singletons and clusters. The hypothesis is that children will acquire singletons followed by clusters in an alternating and recursive pattern, in complement to observed subsegmental cyclicity involving larnygeal and supralaryngeal distinctions. Six children with functional phonological disorders participated in one of three experimental conditions administered as a staggered multiple-baseline, multiple-probe design: treatment of singletons only, clusters only, or the singleton-cluster cycle. Results indicated that a singleton-cluster cycle could be induced experimentally, but it was not generally sustained by a child in expansion of the phonological repertoire. In comparison, laryngeal-supralaryngeal cyclicity was consistently maintained by all children, independent of experimental condition. A theoretical implication of these findings is that cyclicity functions as a governing principle of phonological development, but only if it is inherent to the natural domain of language. The clinical application of cyclicity in structuring treatment is considered.