Opportunities to Combine LENA Recording Technology and SALT

Dr. Kimbrough Oller Professor and Plough Chair of Excellence The University of Memphis School of Communication Sciences and Disorders

The technology produced by the LENA Foundation for all-day recording in the home with a battery-powered device worn in infants' and children's clothing has added a major new method to the study of the acquisition of language. There has been a great deal of emphasis on the use of the automated analysis that LENA supplies, offering counts of adult words, child vocalizations, and conversational turns. There are dozens of publications by now using the method and numerous clinical/educational applications that can be reviewed on the LENA Foundation website. I have participated in several of the studies using the automated method and am a strong advocate of continued development and usage of the technology. On the other hand most of the work I do in my own laboratory uses the LENA recording technology without significantly invoking the automated methods. Instead we use the all-day recordings to acquire random samples of speech and vocal interactions in the home, presumably the most representative samples that can be obtained. Then we have human coders listen to the random samples and code them in considerably more detail than is possible with the automated system. Typically we begin with real-time listening to count utterances of both infants and adults and to obtain an overview of the extent of interaction in each such sample. Then we select samples with activity levels representative of either endogenous vocalization by the infant/child or vocal interaction of the infant/child with caregivers. This method yields perspectives that cannot be obtained as yet with automated tools. I might add that results from human coders will always be the standard against which automated methods of vocal analysis will be judged . So far, our own work has mostly focused on the first year of life and consequently has made use of "coding", but not phonetic transcription or semantic characterization of the randomly selected samples--we characterize illocutionary forces of infant utterances, but there is rarely any straightforward "word" material to be transcribed on the baby's side until the last couple of months of the first year. The caregivers offer different opportunities, however, and even early in the first year, transcription of what caregivers say to infants yields very important perspectives on the nature of the infant's emerging linguistic capability. SALT transcriptions of caregiver utterances along with characterizations of infant vocal illocutionary forces could be extremely valuable to help us interpret the emerging infant awareness of language, even when infant vocal output is devoid of or very limited in semantic content. Caregivers reveal in their utterances their interpretations of infant state and communicative intention, and by the end of the first year, caregivers reveal their own attempts to negotiate potential word meanings with infants whose babbling by that age offers exemplars of possible words.  Thus it seems to me that it will be important in the near future for human coding of both infant and caregiver utterances selected from all-day recordings to be expanded to include both illocutionary and semantic material from parents and infants. A combined SALT and LENA methodology could supply an important new opportunity. Dr. Kimbrough Oller is a permanent member of the Scientific Advisory Board of the LENA Research Foundation of Boulder, Colorado. At the University of Memphis, he directs the Infant Vocalization Project and the Language Evolution Project. Dr. Oller has published over 220 articles, four books and editor of two journal volumes. In 2011, one of Oller's scientific research articles was recognized by Autism Speaks as one of the top 10 achievements in autism. See his full CV here.