Prosodic focus with and without post-focus compression: A typological divide within the same language family?

There is increasing evidence that many languages encode prosodic focus not only with phonetic variations in the focused component itself, but also with a reduction of pitch range and intensity of the post-focus components, a strategy known as post-focus compression (PFC). However, evidence is also emerging that in many other languages prosodic encoding of focus is markedly different, suggesting that PFC might be related to factors such as the presence of lexical tone, stress or the availability of morphosyntactic means of signaling focus. The current study investigated the production and perception of focus in Taiwanese, Taiwan Mandarin and Beijing Mandarin, three languages/dialects that are all tonal and that have similar morphosyntactic means for indicating focus. Results showed clear evidence of PFC in Beijing Mandarin but lack of it in Taiwanese and Taiwan Mandarin, suggesting that PFC is independent of the factors mentioned above. Most interestingly, Taiwan Mandarin seems to have lost PFC due to close contact with Taiwanese despite its effectiveness as demonstrated by the perceptual experiment. The new findings, taken together with other recent finding about prosodic focus, seem to suggest that PFC is a "hard-to- evolve" prosodic feature that may have a single historical origin. Thus there is a need for large scale experimental research to explore the crosslinguistic distribution of PFC, so as to broaden our understanding of not only prosodic typology, but also language contact, bilingualism and language evolution in general.