It has often been suggested that speakers use prosodic tune to convey the information structure of an utterance. Researchers argue that there is a specific pitch accent or tune associated with the focus (or comment) of an utterance, which is distinct from the pitch accent or tune associated with the topic. For example, Steedman (1991) has proposed that the L+H* LH% pattern is “the theme tune” and at least one function of this tune is to mark “what the utterance is about.” (p. 275). Vallduvi and Zacharski (1994) note that this L+H* LH% tune “is generally not correlated with a focus in a focus-ground partition”, thus supporting Steedman’s claim, to the extent that focus and topic/theme are complementary notions. In earlier work, Bolinger (1986 and earlier works), Jackendoff (1972), and Gundel (1978) propose that a rise-fall (A) accent typically falls on the comment of a sentence, whereas accented topics receive a fall-rise (B) accent.
Gundel, Jeanette, Nancy Hedberg and Ron Zacharski. 1997. “Topic-Comment Structure, Syntactic Structure and Prosodic Tune,” Workshop on Prosody and Grammar in Interaction, Helsinki, Finland, August 13-15.(pdf)