Tenseness in vowels: an ultrasonic study

Ultrasonic imaging was used to measure the distance from the external neck wall to the anterior pharyngeal wall (APW). Measurements were made in the centre of the vocalic segment of 50 CVC syllables. 5 'tense' and 5 'lax' vowels of Standard American English were used. The APW was shown to position itself according to a combination of tongue height, frontness and 'tenseness' of the vowel, and coarticulation effects of neighbouring consonants. Tense vowels showed APW advancement compared to lax vowels having similar tongue height and frontness. Coarticulation effects depend on voicing and place of articulation. The ultrasonic equipment used is described briefly. Implications for distinctive feature theory are mentioned.