Allan B. Smith

The frequency of simultaneous disfluency and phonological errors in children: A preliminary investigation

The frequency of simultaneous disfluency and phonological errors was examined in seven young English-speaking children exhibiting coexisting stuttering and phonological disorders. Data were gathered during 30 minutes of mother-child conversation and analyzed in three parts: (1) stuttering, (2) phonological errors, and (3) stuttering and phonological error co-occurrence. Results indicated that stuttering did not occur more frequently on syllables with phonological errors than on syllables without phonological errors. However, the frequency of disfluency on word-initial consonant clusters with phonological errors was significantly higher than on word-initial consonant clusters without phonological errors. Theoretical and clinical implications are discussed.

Durational characteristics of the first productions of novel trochees and iambs in children with and without speech delay

The durational characteristics of novel words produced in repeated trials were evaluated in separate groups of children with, and without speech delay (SD). Children produced disyllabic novel words containing either a trochaic or iambic stress pattern. Results of acoustic analysis indicated a significant interaction between trial number and speaker group. The duration of words produced by children without SD decreased more abruptly across successive trials as compared to children with SD. In addition, duration decreased at a faster rate for trochaic words as compared to iambic words in both groups. Variability of word duration was greater in iambs than trochees. The results are discussed in terms of speech motor learning patterns that may underlie difficulties associated with SD.

The Influence of Utterance Position on Children’s Production of Lexical Stress

Previous studies reporting acoustical data on children’s production of lexical stress examined words produced in isolation (i.e., with no carrier phrase) or in utterance-final position. In such contexts, the final syllable of the words being examined was also the utterance-final syllable. Syllables produced in utterance-final position are known to be longer in duration and lower in intensity and F₀ compared to other syllables within utterances. Therefore, utterance-final effects may have obscured previous results on children’s production of stress. Twenty children at approximately 6 years of age produced novel trochaic and iambic words in utterance-final and utterance-non-final position. Comparing productions across the two utterance positions suggested that reliance upon the utterance-final context was a confounding factor in past studies. Utterance-final position facilitated the iambic pattern of duration (short-long) and the trochaic pattern of intensity and F₀ (high-low). Utterance position sometimes affected trochees differently than iambs, especially in the duration of word-final syllables. The results are discussed in terms of past explanations of utterance position effects on acoustic characteristics of syllables.

Relationship between longest utterances and later MLU in late talkers

Abstract The task of developing prognoses for late-talking children has long been a challenge for speech-language pathologists, developmental psychologists, and pediatricians. Improved predictors would help to assess long-term risk and determine appropriate intervention services. The present study evaluated children’s length of longest utterances (LLU) as a predictor of mean length of utterance (MLU) one year later. Relationships between LLU at 30 months, MLU at 30 months and MLU at 42 months were examined in 43 late talkers (LT) and 33 age-matched children whose language was typically developing (TD). LLU was a significant predictor of MLU at 42 months with particularly strong correlations within the LT group. Similar results were obtained when controlling for language sample size, which was positively related to LLU. For the LT group, a regression model combining 30-month LLU and MLU was better at predicting 42-month MLU than 30-month MLU alone. The results are discussed in terms of frequency distributions of utterance lengths within language samples. 

Factors underlying short-term fundamental frequency variation during vocal onset and offset

Abstract Fundamental frequency (F0) typically decreases during vocal cycles immediately preceding and following voiceless obstruents for reasons that remain unclear. One explanation is that aerodynamic changes surrounding obstruent production underlie F0 variation. Alternatively, laryngeal maneuvers used to adduct/abduct the vocal folds may change vocal fold tension, leading to F0 variation. In this study, cycle-to-cycle variation in F0 was examined in several phonetic contexts that differ in aerodynamic and laryngeal factors. Results showed that at F0 onset, F0 variation depended more upon laryngeal factors than aerodynamic factors. At F0 offset, there were no significant differences across phonetic contexts. It is suggested that the factors influencing F0 variation at phonation onset may differ from those influencing F0 variation at phonation offset.

Speech timing and pausing in children with specific language impairment

Articulation rate, speaking rate, as well as the duration and location of pauses, were analysed in 10 children with specific language impairment (SLI) and a comparison group of seven younger children producing utterances of similar lengths. Children with SLI were significantly slower in articulation rate, but not speaking rate or pausing time, indicating a group difference attributable to longer syllable duration. The correlation between the duration of the pause preceding a childs speaking turn and the length of the subsequent child utterance was calculated as an indication of childrens use of the pause for planning the utterance. The correlation was not significant in either group, and not significantly different between groups. An analysis of the position of pauses within speaking turns showed more syllables following than preceding the pause, with no significant group differences. Theoretical implications are discussed.

Precursors of Dyslexia in Early Conversational Turn Exchange.

This study investigated conversational timing patterns among 22 children aged 3 years as each interacted with an adult. Most of the children were at high familial risk for dyslexia. When reading was tested in grade school, a group of 11 children was found to have dyslexia and the remaining 11 children read normally. At the age of 3 years, the 2 groups showed different patterns of timing in conversation. In comparison with children without dyslexia, those with dyslexia were significantly more likely to wait for adults to finish their speaking turn, and then offer a response that was semantically related to the adults speech. The 2 groups did not differ in the percentage of no-responses defined as an absence of speech during the 2 seconds following the completion of an adult speaking turn. The results are discussed in terms of speech timing during child–adult interaction and spoken language deficits in dyslexia.