Autosegmental
phonology is a theory of non-linear phonological representation. It was developed out of research in
Generative Phonology at MIT in the mid and late 1970s, as a response to certain
problems in the phonological theory of that time.
Autosegmental
phonology was initially developed in response to the challenge of developing an
adequate theory of tone. Its
immediate source of inspiration was the work of Williams 1971 and Leben 1973;
these were the first to introduce non-linear structures into generative
phonology in their treatments of tone systems in West African languages such as
Margi, Igbo and Mende. In the
model proposed by these writers, underlying tones were represented on separate
tiers from the feature matrices representing vowels and consonants; they were
subsequently merged with these matrices by Tone Mapping Rules that applied in
the course of derivation, creating single-tiered representations in surface
structure.
The principal
innovation of autosegmental phonology, as presented in Goldsmith 1976, was the
idea that tone mapping rules do not merge tonal and segmental representations,
but associate their elements by means of formal entities known as Association
Lines. In this framework,
phonological representations consist of parallel tiers of phonological
segments, both tonal and segmental.
Tonal
Representation
t
t t t
H L H L
H=high tone L=low
tone t=any
tone-bearing unit (vowels or syllables)
Elements
of each tier, called AUTOSEGMENTALS, are sequentially ordered; elements of
adjacent tiers are simultaneous if and only if they are linked by association
lines. In this model, all tiers
remain independent throughout derivations: at no point is the tonal tier merged
with segmental tier.
A further innovation
of autosegmental theory is the set of universal principles termed
Well-Formedness Conditions, which govern the multi-tiered structure of the
representation. These principles
not only define the set of theoretically possible inter-tier configurations;
they also trigger the operation of a set of universal repair mechanisms, often
termed Association Conventions, whenever configurations that violate them
arise.
In subsequent work,
autosegmental phonology underwent further development; by the mid-1980s it
could be considered a fully general theory of phonological representation,
radically different from the linear representational systems of more
traditional approaches. The
primary innovation of the generalized model has been the view that not just
tone and other so-called ‘prosodic’ features, but all phonological feature are
arrayed on separate autosegmental
tiers. In this conception,
which draws upon earlier research in Metrical Phonology and Prosodic Phonology.
Autosegmental
Representation
β
Structural
Tiers
α
α
X X X
X Skeletal Tiers
Y Y Y Y
Z Z Z Z Substantive
Tiers
W W W
Further
developments in autosegmental phonology include the grid-based theory of stress
proposed by Halle & Vergnaud 1987, and the model of intonation and prosodic
structure developed by Pierrehumbert & Beckman 1988. For a more recent overview and several
new proposals, see Goldsmith 1990.
As remarked by Van der Hulst & Smith 1982, progress in autosegmental
phonology has owed much to its ‘problem-solving efficiency’- i.e., its success
in finding solutions for previously unsolved representational problems, and
integrating them into a consistent, over-all theoretical framework.
REFERENCE
EDLSTEIN JEFFEREY P. & MCGARY JANE etc. EDS. 1992. INTERNATIONAL
ENCYCLOPEDIA OF LINGUISTICS. OXFORD UP.[ET1]