Isoglosses and language change: Evidence of the rise and loss of isoglosses from a comparison of early Greek and early English

We analyze the rise and loss of isoglosses in two Indo-European languages, early Greek and early English, which, however, show considerable distance between their structures in many other domains. We follow Keidan’s approach (2013), that has drawn the attention on the fact that the study of isoglosses (i.e., linguistic features common to two or more languages) is connected with common innovations of particular languages after the split into sub-groups of Indo-European: this type of approach aims at collecting isoglosses that appear across the branches of Indo-European. We examine the rise of the isogloss of labile verbs and the loss of the isogloss of the two classes of aspectual verbs in early Greek and early English. Our study shows that the rise of labile verbs in both languages is related to the innovative use of intransitives in causative constructions. On the other hand, the innovations in voice morphology follow different directions in Greek and English and are unrelated to the rise of labile verbs. In contrast to labile verbs, which are still predominant for causative-anticausative constructions in both languages, the two classes of aspectual verbs are lost in the later stages of Greek but are predominant even in Present-day English. Again, a “prerequisite” change for the isogloss can be easily located in a structural ambiguity that is relevant for aspectual verbs in early Greek and early English. However, another independent development, the changes in verbal complementation (the development of infinitival and participial complements) in Greek and English, determined the loss of this isogloss.