Long-standing uncertainty about the phonetic correlates of stress (also known as “phonetic cues to prominence”) is fundamentally due to failure to appreciate the unusual PHONOLOGICAL nature of stress in many languages.  In particular, stress in the West Germanic languages, though it is superficially a matter of local suprasegmental features that are realised on individual syllables to varying degrees, is best seen as the manifestation of a hierarchical prosodic structure that (a) defines prominence relations between prosodic constituents and (b) governs the association of intonational features with the segmental string (‘tune-text association’). Differences in tune-text association give rise to cross-linguistic misperceptions of stress.

Metrical stress theory, as originally proposed by Liberman and especially as interpreted in subsequent work, emphasised the ‘rhythmic’ aspects of the hierarchical prosodic structure, but Liberman’s more important insight is that the structure governs tune-text association.  Since all languages must have principles of tune-text association (because all spoken language involves both pitch and segmental syllables), a theoretical focus on how (and whether) tune-text association reflects prosodic structure clears up some puzzles (like why English phoneticians think French has stress) and allows for a richer and more insightful prosodic typology than a simple but inadequate dichotomy between tone languages and stress languages.