5th International Conference on Spoken Language Processing
Schwa is commonly regarded phonologically as an unspecified vowel, and phonetically as "targetless", i.e., as the product of its context. Methods used in studies investigating the issue are discussed, and it is argued that the evidence for targetlessness is unconvincing. An experiment is presented in which schwa is produced in symmetrical vowel and consonant contexts under varying speech rate conditions. It is shown that the contextual influence on schwa depends on its duration, a result that is not compatible with the concept of a targetless vowel. This conclusion is discussed in relation to the possible phonological status of the target specification.
Bibliographic reference. Barry, William J. (1998): "Time as a factor in the acoustic variation of schwa", In ICSLP-1998, paper 0554.