We can read a 10-digit sequence in the style of an American telephone number, 3+3+4 — e.g. 752-955-0354:
Or we could read the same sequence in a 3+2+3+2 pattern, 752-95-503-54:
It won't surprise you to learn that this changes the pattern of average digit durations:
The graph above shows average duration by digit position for 200 10-digit strings, 100 in each phrasing, organized so that every digit occurs equally often (ten times) in each position, and every pair of digits occurs equally often spanning each pair of positions. Of course the phrasing is also expressed in the pitch contour and in other ways as well — but the pattern of timing is an especially clear and easy-to-read sign of the structure. (And a similar speech-rate shape applies in ordinary speech as well, as discussed in "The shape of a spoken phrase", 4/12/2006.)
In the Penn Linguistics Department's speaker series a few weeks ago, Janet Dean Fodor gave a fascinating talk titled "Multiple Center-embedding: What's Pronounceable is Comprehensible!" Here's her abstract:
The extreme sentence processing difficulty of doubly center-embedded relative clause (2CE-RC) constructions has elicited many proposed explanations over many decades. Improbably, we offer a phonological explanation. We maintain: (a) that a sentence can't be easily parsed syntactically if it can't be assigned a supportive prosodic contour, and (b) that the flat structure of prosodic phrasing is hard to fit to the densely hierarchical structure of a 2CE-RC sentence.
Examples like (1) are cited in the literature; (2) is from an experiment by Gibson and Thomas (1999). Short or long, both are pronounced awkwardly, with 'list intonation'. Syntactic parsing is so difficult that they are often judged more grammatical when the second VP is (ungrammatically!) omitted, as in (3): this is the "missing VP illusion".
(1) ✔☹ The boy the dog the cat scratched bit died.
(2) ✔☹ The ancient manuscript that the grad student who the new card catalog had confused a great deal was studying in the library was missing a page.
(3) *☺ The ancient manuscript that the grad student who the new card catalog had confused a great deal was missing a page.
We show that the correct nested syntactic structure [NP1 [NP2 [NP3 VP1] VP2 ] VP3] is achievable if prosodic phrasing can package up the center elements [NP2 NP3 VP1 VP2] together. Because prosodic phrases must meet length requirements, this is feasible only if the center constituents are all short, and the outer constituents (NP1 and VP3) are long enough to constitute separate prosodic phrases. This is the case in (4). Experiments confirm that examples like (4) are easier to pronounce and understand than examples like (5), which has the same overall sentence length but has its weight in the wrong places: skinny outer constituents and chubby inner ones. (Read them aloud!)
(4) ✔☺ The rusty old ceiling pipes that the plumber my dad trained fixed continue to leak occasionally.
(5) ✔☹ The pipes that the unlicensed plumber the new janitor reluctantly assisted tried to repair burst.
An explanation is offered on the assumption that syntax-prosody alignment is achieved by syntactic readjustment to the needs of prosody (Chomsky and Halle 1968, contra Selkirk 2000).
Janet engaged the audience by having its members enlisted to read the example sentences. It was clear, I think, that the successful attempts made use of the capability to distinguish among several levels of phrasal prosody, using timing (as in the phone-number examples), pitch, and so on. But I was disappointed that Janet's presentation assumed the idea that only one level of prosodic phrasing is available in English, and when I asked her about this, she suggested (I think) that perhaps German speakers use multiple levels, but that English speakers don't, or something of the sort.
A fuller explanation can be found in Janet Dean Fodor, "Pronouncing and comprehending center-embedded sentences", in Monserrat Sanz et al. Eds. Language Down the Garden Path, 2013, in the section on "a better prosody":
But I would be shocked to learn that this is really a difference between the German and English languages.