Daniel Pritchard at the MIT website:
It was in grade school classes that most of us first learned about the syllable — the tiny unit of organization for speech sounds, bundles of which can be combined to construct words, phrases, sentences, paragraphs, mystery novels, biology textbooks, national constitutions, etc.
The humble syllable performs impressive work, and for the field of linguistics it also holds a special analytical importance: it has long been considered to be one of the basic units of language. Speech has many qualities — including sound, meaning, rhythm, and syntax — and for each of those qualities there is a basic building block, a sort of linguistic atomic unit. For many years, the prevailing view in the linguistic field has been that the syllable is the basic building block of language in the area of rhythm.
But MIT linguistics professor Donca Steriade is no longer so sure about that. Along with a number of like-minded linguists, and bolstered by a growing body of research, Steriade believes that the emphasis on syllables is misplaced. Instead she suggests that a different element — known as the “interval” — may be the basic unit of rhythm in human language.