The relation of lung volume initiation to selected acoustic properties of speech.

This study examined the relationship of speech breathing to other elements of speech production. It was hypothesized that initiating speech from different lung volumes would have an effect on different elements of the acoustic output. It was postulated that effects may be brought about by mechanical interaction as well as a dispersion of effort to mechanically unlinked elements of speech production, such as articulatory behavior. To this end, selected acoustic variables were studied in eight young healthy women who initiated speech from low, typical, and high lung volume levels. The acoustic variables studied were selected because they have been shown to be sensitive indicators of speech production performance. It was found that with increasing lung volume initiation levels, average sound pressure level, average fundamental frequency, and declination rate of fundamental frequency increased. It was also observed that vowel space was significantly smaller during low lung volume initiation levels relative to typical lung volume initiation levels. Vowel space reduction is discussed relative to "gaining down."