Measurement error for vowel durations

Abstract

In recent studies involving the correlation of speech segment durations, the measurement error in locating segment boundaries has usually been ignored or assumed to be constant and small. Since the relative magnitude of the error in locating such a boundary can have a profound effect on derived intersegment correlations, an experiment was designed to estimate these errors directly. Several tokens of four sentences containing syllables differing in the quality, length, degree of stress, and consonantal context of their nuclear vowels were copied onto two‐track tapes and sent to several professional phoneticians with instructions to measure the durations of the indicated vowels, on first one track and then, at least two weeks later, the other. The resulting measurement errors varied systematically in several ways: (1) long, stressed vowels had greater errors than short, unstressed ones; (2) initial voices stops (/b/0 were easiest to segment and approximants (/w/) hardest, with voiceless stops (/k/) and fricatives (/f/) intermediate; (3) great differences among phoneticians appeared to depend on the segmentation criteria used, not their instrumentation.