手法を比較

	Vowel Formant Analysis	Apparent-Time Analysis
分野	言語学	言語学
系統	Process / pipeline	Process / pipeline
提唱年	1952	1963
提唱者	Acoustic phoneticians (Gordon Peterson & Harold Barney)	William Labov
種類	Acoustic measurement workflow for vowel quality	Inferential design for detecting language change in progress
原典	Peterson, G. E., & Barney, H. L. (1952). Control methods used in a study of the vowels. Journal of the Acoustical Society of America, 24(2), 175–184.	Labov, W. (1963). The social motivation of a sound change. Word, 19(3), 273–309.
別名	Formant Analysis, Vowel Acoustic Analysis, F1-F2 Vowel Space Analysis	Apparent-Time Construct, Apparent-Time Hypothesis, Age-Stratified Change Analysis
関連	4	4
概要	Vowel formant analysis is the acoustic measurement workflow for characterizing vowel quality. Vowels are resonances of the vocal tract, and their identity is carried by the formants — the spectral peaks created by those resonances. The first formant F1 is inversely related to vowel height (low F1 for high vowels, high F1 for low vowels), and the second formant F2 tracks frontness/backness (high F2 for front vowels, low F2 for back vowels). By measuring F1 and F2, plotting vowels in the F1×F2 acoustic space, and normalizing across speakers with procedures such as Lobanov, Bark, and Nearey, analysts obtain a reproducible map of a vowel system that can be compared within and across speakers, dialects, and time.	Apparent-time analysis is the foundational variationist method for detecting language change in progress without waiting for time to pass. Introduced by William Labov in his 1963 study of Martha's Vineyard, it compares the speech of speakers of different ages sampled at a single moment and treats the age dimension as a proxy for historical time: if younger speakers use a variant more than older speakers, that age gradient is read as evidence of change unfolding across generations. The inference rests on the apparent-time hypothesis — that an individual's vernacular is largely fixed in adolescence and remains stable through adult life — so that the speech of today's seventy-year-olds reflects the community norms of roughly fifty years ago.