When Predictability and Prosody do not align: 

The case of structural nesting

Durational properties of speech are largely dependent on complexity, often modelled as a function of predictability. Higher predictability is reliably associated with shorter duration. Prosodic prominence, on the other hand, is associated with lower predictability and thus with longer duration (e.g. Aylett & Turk, 2004, a.o.). Results from the parsing literature show that a similar relation between duration and predictability is also found in comprehension: the amount of time spent reading a particular region is a function of the strength of prior expectations (e.g. Hale 2001, Levy. 2008, a.o.). 

I will discuss evidence that there exists a set of well-defined structural environments in which shorter durations are correlated with lower predictability: the contrast between syntactic nesting and sisterhood. These environments include well-known garden-path sentences of the Main Verb/Reduced Relative Clause variety (the horse raced past the barn (and) fell) and the Complement Clause /Relative Clause variety (John told the woman that he was running with Billy/ John told the woman that he was running with to wait).

In line with Turk & Shattuck-Hufnagel (2014), I will argue that the effects of predictability on duration are indirect, i.e. mediated by prosodic structure. Contrary to their perspective, which still assumes a substantial alignment between prosodic structure and predictability (with prosodic structure helping processing of less predictable structures via e.g. boundary insertion), I will show that in the case of syntactic nesting (and garden-path sentences in particular) a clear conflict emerges between predictability and prosodic structure and that duration is primarily determined by considerations of prosodic structure, with results which mismatch what is expected on the basis of predictability.