Age-Grading and Linguistic Continuity

The origin and development of speech habits in individuals, through their life cycles from birth to death, can appropriately be termed linguistic ontogeny. In contrast to this, the subject matter of historical linguistics—changes through decades and centuries in the speech patterns of communities—is of course linguistic phylogeny. The present paper deals with certain relations between these two: specifically, with the mechanisms whereby continuity of linguistic tradition is maintained in a community in the face of the constant turnover of population through birth and death, immigration and emigration. Jespersen has discussed this problem, and has connected it with historical linguistics by asking what relation there may be between these mechanisms and the fact that languages change in the course of time. But Jespersen, as is well known, did not accept the assumption that phonetic change is regular.