Physically many cats are able to get pregnant as young as only six or seven months old. However, it is better and healthier for pregnancy to occur when they're a little older. Often younger cats are not good mothers; the maternal instinct seems to be better developed when they're one year or older.
Initially, all modern linguistics was historical in orientation. Even the study of modern dialects involved looking at their origins. Ferdinand de Saussure 's distinction between synchronic and diachronic linguistics is fundamental to the present day organization of the discipline.
Comparative linguistics, in the relevant sense, is understood as the study of linguistic relatedness, that is to say, of genetic or ancestral connections and related matters of subgrouping extending to the reconstruction of unattested ancestral languages or proto-languages.