Effect of modest sidetone delays in modifying talker rates and articulation in a communications task

Abstract

Sidetone delay (delayed auditory feedback) is known to cause speakers to talk more slowly, and at delays of about 200 ms also causes severe articulation disturbances. If shorter delays can slow speech without adverse effects on articulation, this effect could be used to make talkers speak more slowly in certain communications situations. Subjects read lists of 1, 2, 3, or 4 syllable words and of sentences under each of 6 delay conditions (0, 7.5, 15, 30, 60, and 100 ms). Delays of 15–30 ms caused a significant slowdown in speaking rate with no adverse effects on articulation. Delays of 60–100 ms caused a greater slowdown but also had a noticeable adverse effect on speech quality, especially for sentences and polysyllablic lists. In communications situations where the quality of transmitted speech is degraded (e.g., vocoded speech), sidetone delay may be useful in modifying the talk's behavior to improve overall speech quality.