What is the importance of pre-linguistic vocalization?
Background: The characterization and significance of pre-linguistic vocalization has long been the subject of research and debate. Pre-linguistic vocalization can generally be classified into non-speech-like vocalizations, including vegetative sounds, and speech-like vocalizations known as protophones. Most protophones begin with vowel-like vocalizations and culminate in well-formed, reduplicated consonant-vowel combinations referred to as canonical babbling.
Study design: Retrospective review
Setting: Department of Otolaryngology-Head and Neck Surgery, University of Michigan Medical School and University of Michigan Health System, Ann Arbor; Department of Speech-Language Pathology, Division of Pediatric Otolaryngology, University of Michigan Health System
Synopsis: Researchers utilized a novel method to evaluate speech and language development in the absence of pre-linguistic practice. Seven children had high-grade, long-segment, subglottic stenosis with tracheostomy placement during the pre-linguistic stage of language development. All seven were aphonic until they subsequently underwent cricotracheal resection and decannulation.
After an initial delay in speech acquisition, vegetative functions were the first laryngeal sounds to emerge, followed by an accelerated progression through canonical babbling to verbalizations. Non-speech-like laryngeal sounds were superseded by protophone development.
The study compared the children’s pre- and post-surgical methods of communication. The researchers concluded that cricotracheal resection facilitates the study of early vocal practice deprivation on subsequent speech and language development. The study did not demonstrate a correlation between use of preoperative sign language and time to speech development.
Bottom line: The observations in this study support the hypothesis that babbling is necessary for speech and language development regardless of the age at which verbalization is physiologically possible.
Citation: Bohm LA, Nelson ME, Driver LE, et al. Babbling, vegetative function, and language development after cricotracheal resection in aphonic children. Laryngoscope. 2010;120(12):2494-2497.
—Reviewed by Sue Pondrom