Child Phonology Laboratory

Child Phonology Lab

The Child Phonology Laboratory, headed by Dr. Karen E. Pollock, is designed for studying speech sound production in children with normally developing speech and children with phonological disorders. The laboratory contains hardware and software for many different types of speech sound analysis, including acoustic measures as well as perceptually-based phonetic transcription and phonological analysis. Recent projects have focused on vowel errors in children with phonological disorders and phonological characteristics of African American Vernacular English.  In addition, a newer line of research in the lab focuses on speech and language acquisition in children adopted from China.


Recent Research Projects

 Speech-Language Acquisition in Children Adopted from China

Little is known about the course of language development in young children adopted from China.  According to anecdotal reports, most children acquire English with little or no difficulty, although there may be initial delays relative to children born and raised in the U.S. However, some internationally adopted children experience significant difficulty in acquiring language, and ultimately require speech-language intervention.  There is an urgent need for normative data on early language development in children adopted from China, especially during the first year or two post-adoption. A series of studies is underway to examine the nature and course of speech and language development in children adopted from China.  Click here for more information about recently completed and ongoing studies.

Speech-Language Acquisition in Children Adopted from Haiti

The majority of research on internationally adopted children has focused on children from China and Eastern Europe.  Although adoptions from China predominate across Canada on the whole, in Alberta nearly half of the children adopted internationally come from Haiti.  Data collection has been completed on a study of young children adopted from Haiti. Click here for more information about the study.


Language Development Survey:  Children Adopted from Ethiopia  *VOLUNTEERS NEEDED!*

The majority of research on internationally adopted children has focused on children from China or Eastern Europe.  We recently expanded our longitudinal survey of speech and language development in internationally adopted children (originally designed for children adopted from China) to include children adopted from Ethiopia.  Click here for more information or to find out how to participate.


Vowel Misarticulations in Children

Vowels have long been ignored in research and clinical practice with phonologically disordered children. However, recent reports of vowel misarticulations in preschool children with phonological disorders (without diagnosed motor or sensory deficits) have highlighted the importance of studying vowels. The Memphis Vowel Project was designed to investigate the nature and clinical significance of vowel misarticulations in the speech of preschool children with phonological disorders. Videorecorded speech samples from 314 children (165 normally developing and 149 phonologically disordered) were analyzed with customized phonological analysis software. Results showed that the incidence of vowel errors in normally developing children over three years of age was less than 5%, whereas the incidence in three- to six-year-old children with phonological disorders ranged from 11 to 32%, depending on the criteria used. Furthermore, the incidence of vowel errors was related to severity of consonant errors, with as many as 50% of children with severe consonant errors exhibiting concurrent vowel errors. The types of vowel errors produced by children with phonological disorders were similar to those of younger, normally developing children (under three years of age). This project was funded by the National Institutes of Health, Grant # R29 DC01424.

Phonological Features of African American Vernacular English (AAVE) (Pollock, et al)

Most commonly referenced descriptions of AAVE phonology are based on data collected in the 1960s from adolescents in northern urban areas (e.g., Labov, 1972; Wolfram, 1969).  As a result of the dynamic nature of spoken language, these oft-cited descriptions may no longer be accurate for AAVE speakers today or for AAVE speakers in different regions of the U.S.  Using existing literature from sociolinguistics and child language, along with our own data from Memphis AAVE-speaking children and adults and Bailey's data from Texas AAVE-speakers, we have compiled an updated list of AAVE phonological features.  Along with a description and examples, the list provides information on internal linguistic constraints on the variable application of each feature. If available, information is also provided about whether or not the feature is also used in other American English dialects, is currently undergoing a change (i.e., expanding or receding usage), or varies according to geographic or urban/rural areas.  In the near future, audio files will be added to the list to accompany the phonetically transcribed examples.  The list is available at rather than in printed form, so that it may be modified or updated as new information becomes available. 

Vocalic and Postvocalic /r/ in African American Memphians

Variation in the use of vocalic and postvocalic /r/ has long been recognized as a marker of Southern American speech, with Southern speech being historically "r-less." Over the past century, although Southern American speakers in general have become increasingly "r-full," African Americans in the south remain consistently less r-full than southern white speakers. Pollock and Berni (1997) examined the production of vocalic and postvocalic /r/ in African American and white adults born and raised in or around Memphis, TN. Single word productions of 42 words were phonetically transcribed from videotape and the percentage of fully constricted (rhotacized) productions calculated in several contexts (stressed and unstressed vocalic /r/, post-vocalic /r/ following two front vowels and two back vowels). The mean percentage of fully constricted vocalic and postvocalic /r/ was 99% for white speakers and 78% for African Americans. African Americans were most likely to use constricted /r/ in the stressed vocalic context (e.g., her) and following front vowels (e.g., here, hair). They were least likely to use it after back rounded vowels (e.g., four) and in the unstressed vocalic context (e.g., flower). In addition, many African American speakers centralized or reduced front vowels before /r/, resulting in the perceptual similarity of certain words (e.g., here, hair, her). The same speakers often followed rhotic vowels with a schwa offglide (e.g., chair was produced as churra), further contributing to the distinctiveness of their productions relative to those of white speakers. This project was partially supported by the National Institutes of Health, Grant # R29 DC01424.

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