Kubozono [1] found that in sequences of four accented words in a syntactic-phrase-internal uniformly left-branching (LB) structure, the f0 peak of the third word is realized at the same height as or higher than the preceding word, showing no apparent catathesis (or downstep). He argues for an f0 raising effect, called rhythmic boost, that is the consequence of the organization of this 4-word syntactic structure into (recursive) two prosodic minor phrases (MiP, aka accentual phrase) that branch into two MiPs each. In this paper we report on two experiments. Experiment 1 demonstrates the rhythmic boost effect experimentally, giving solid evidence for Kubozono’s claim about boost in these sequences. We find that the rise at the third word in LB sequences of four accented words is significantly higher than at the third accented word of 3-word phrase- internal LB sequences, and we find too that this rise is also significantly lower than the one found with a third word that initiates a syntactic maximal projection (XP) and would therefore be at the edge of prosodic major phrase (MaP, aka intermediate phrase). Experiment 2 investigates a possible influence of length of MiP on the reported boost in f0, to see if that boost could be derived from the anticipatory length-based f0 raising (ALR) effect found by Selkirk et al. [2]. We find that that ALR effect cannot explain the magnitude of the rise at the third noun in the 4-noun sequences, and conclude that there is indeed a place for a branching-sensitive rhythmic boost in f0.

s Kubozono, H., 1989. Syntactic and rhythmic effects of downstep in Japanese, Phonology 6, 39-67. Selkirk, E., Shinya, T.; Kawahara, S., 2003. Phonological and phonetic effects of minor phrase length on F0 in Japanese, Proc. Speech Prosody 2004, Nara, Japan.