Differential prosodic encoding of topic and focus in sentence-initial position in Mandarin Chinese

This paper reports an experimental investigation of the prosodic encoding of topic and focus in Mandarin by examining disyllabic subject nouns elicited in four discourse contexts. These subject nouns also varied in terms of their tonal composition as well as the length of their embedding sentences. The central questions addressed are how prosodic effects of topic and focus differ from each other and how they interact with sentence length, downstep and newness to determine sentence-initial F₀ variation. Sixty short discourses were recorded with variable focus, topic level, newness, downstep, and sentence length conditions by six native speakers. The results of extensive acoustic analyses show that (1) the difference between topic and focus lies in that focus both raises on-focus F₀ and lowers post-focus F₀ while topic raises the F₀ register at the beginning of the sentence while allowing F₀ to drop gradually afterwards, (2) topic has higher pitch register in isolated and discourse-initial sentences than in non-initial sentences, (3) longer sentences have higher sentence-initial F₀ than shorter sentences, but the differences are small in magnitude and are independent of topic and focus, (4) the effect of downstep is independent of topic and focus, but is large in magnitude and accounts for a significant amount of the F₀ declination in a sentence, (5) newness has no F₀ manifestation independent of other factors, but a newly mentioned word is slightly longer than a previously mentioned word, and (6) the effects of topic, focus, downstep and sentence length are largely cumulative. We argue that these findings are harmonious with an articulatory-functional view of speech prosody represented by the Parallel Encoding and Target Approximation model (PENTA).