Interrupted Transmission and Rule Loss in Māori: The Case of ka

The Māori tense/aspect marker ka has historically two allomorphs: one, /ka:/, which is used when the rest of the verb phrase consists of only two morae, and the other, /ka/, for longer phrases. Recordings of native speakers born toward the end of the nineteenth century show that this distribution was at that time observed with a high degree of consistency. However, more recent speaker groups show variable behavior in this respect, with modern younger speakers tending to show abandonment of the allomorphy in favor of consistent use of the short form. This shift is attributable both to a proportional increase in the use of longer phrases over the same period and to the decreasing use of Māori generally, so that opportunities to acquire the inherited rule have diminished considerably.