手法を比較

	Apparent-Time Analysis	Real-Time Study of Language Change
分野	言語学	言語学
系統	Process / pipeline	Process / pipeline
提唱年	1963	1994
提唱者	William Labov	William Labov (and the variationist tradition)
種類	Inferential design for detecting language change in progress	Longitudinal design for observing language change directly
原典	Labov, W. (1963). The social motivation of a sound change. Word, 19(3), 273–309.	Sankoff, G., & Blondeau, H. (2007). Language change across the lifespan: /r/ in Montreal French. Language, 83(3), 560–588.
別名	Apparent-Time Construct, Apparent-Time Hypothesis, Age-Stratified Change Analysis	Real-Time Analysis, Trend and Panel Study, Longitudinal Language Change Study
関連	4	4
概要	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.	The real-time study of language change observes change directly by comparing comparable data from the same speech community gathered at two or more actual points in time. Where apparent-time analysis infers change from age differences in a single snapshot, real-time study watches the community across the calendar, either by drawing a fresh sample of the same community years later (a trend study) or by re-recording the very same individuals (a panel study). It is the gold standard for confirming that a change has occurred and for distinguishing community-wide generational change from change within individual speakers over their lifespan.