The difference between a question and a statement: A cross-dialect survey
Greg Kochanski, Esther Grabe, John Coleman · The Journal of the Acoustical Society of America · 2004
Seven British English dialects were studied to see what prosodic distinctions are made between statements and questions in read speech. A set of Bayesian classifiers was built upon feature vectors obtained from a spectral analysis of measures of (1) f0, (2) loudness, (3) spectral slope and (4) voicing periodicity. It was found that the prosodic information useful for the question/statement distinction is distributed broadly across the utterance, and that loudness and spectral slope can be nearly as informative as f0 (voicing is less informative). The three important acoustic features carry somewhat less than one bit of information each, so prosodic information could be valuable to the listener, and the listener may be able to make the question/statement decision early in the utterance. The contrast differs from one acoustic property to the next: f0 is marked primarily by slow variations. Conversely, the spectral slope and loudness measurements primarily use shorter-wavelength features, corresponding to structures that are a syllable or two long. We also find substantial differences in the prosodic information that different dialects use, and substantial differences between speakers of the same dialect. [Research supported by the UK Economic and Social Research Council, Grant RES 00-23-1049.]