autosegmentalmetrinen

Autosegmental-metrical theory (AM theory) is a framework in phonology that models the interaction of segmental phonology with prosody by combining autosegmental representations with a metrical grid. It extends earlier ideas about representing phonological features on separate tiers and assigns rhythmic structure to a hierarchical set of metrical feet, capturing how stress, tone, and other supra-segmental properties relate to the linear sequence of segments.

In AM theory, segments form the primary tier, while additional features such as tone or vowel length reside on separate autosegmental tiers. Association lines link segments to these features, allowing processes like tone spreading, tone shifting, or nasalization to operate across neighboring segments without forcing all features to co-occur on a single segment. At the same time, a metrical grid encodes the language’s stress and rhythm through a hierarchy of feet (for example, trochaic or iambic patterns) and higher prosodic constituents. The interaction between association structure and the metrical grid yields the observed surface prosody.

Historically, AM theory emerged in the late 20th century as an integration of autosegmental phonology with metrical phonology, building on earlier work in autosegmental representations and providing a unified account of both segmental and prosodic phenomena. It has been applied to analyze tonal systems, pitch accents, stress assignment, and languages with complex syllable weight or vowel length contrasts. While later frameworks have evolved, AM theory remains influential for its explicit multi-tier representations and its capacity to model cross-linguistic prosodic patterns within a single formal apparatus.