How to measure frequency? Different ways of counting ergatives in Chintang (Tibeto-Burman, Nepal) and their implications

The frequency of linguistic phenomena is standardly measured relative to some structurally defined unit (e.g. per 1,000 words or per clause). Drawing on a case study on the acquisition of ergativity by children in Chintang, an endangered Tibeto-Burman language of Nepal, we propose that from a psycholinguistic point of view, it is sometimes necessary to measure frequencies relative to the length of the time windows within which speakers and hearers use the language, rather than relative to structurally defined units. This approach requires that corpus design control for recording length and that transcripts be systematically linked to timestamps in the audiovisual signal.