OT has implications for virtually every area of phonological
research. The basic principles of the theory produce desirable
outcomes when applied to a wide range of problems:
effects vs prosodic effects,
list is far from exhaustive.
there is a broad consensus on the intensional definition of
phonological opacity, the extension of the concept is currently
because a phonological generalization can be classified as opaque or
transparent only against a complex and usually disputed background
of assumptions concerning the theory of representations, the constraint set, the
contents of the lexicon, the role of morphosyntax, the role of
phonetics, and the relative scope of synchronic and diachronic explanation:
see  and . Accordingly, Stratal OT does not
set out to provide a comprehensive theory of opacity; no such theory exists at present, nor is one likely to come within our grasp
in the near future.
OT does, however, make an important contribution in this area: a
stratal-cyclic analysis of a misapplication effect arising from
affixation or word concatenation automatically generalizes to
instances of the same misapplication effect in morph-internal
environments.  highlights the learnability advantages of
effects vs prosodic effects
of the toughest problems in the analysis of morphosyntactically
conditioned phonological phenomena is how to distinguish between the
effects of morphosyntax on phonological representations (prosody) and
the effects of morphosyntax on phonological derivations (what we may
informally and pretheoretically call ‘synchronic
Stratal OT enjoys significant strengths in this area because if
offers demarcation criteria that are not available to other
is visible to phonetics; cyclic domains are not.
domains are exactly coextensive with morphosyntactic
constituents; prosodic units need not be.
effects obey cyclic locality;
prosodic effects do not.
illustrates the advantages of these criteria with an extended
case-study; see also .
classical OT under Richness of the Base, all levels of phonological
representation mix contrastive and predictable information.
This can cause ranking paradoxes when phonological processes apply
in a non-structure-preserving way: i.e. when tokens of a segment x
arise predictably in some environment through allophony or
neutralization, but x never occurs contrastively elsewhere.
In such cases, classical OT may encounter a ranking paradox: the constraint *[x]
must rank high enough to ban
contrastive tokens of x, but it must simultaneously rank low
enough to enable x to emerge as the
output of allophony or neutralization.
OT does not face this problem because segments excluded from the
phonemic inventory of a language are filtered out by the stem-level
hierarchy, but may be permitted to arise again through allophony or
neutralization at the
word or phrase levels: see .
phonological processes typically exhibit a cluster of characteristic
properties, discussed in :
processes may or may not display cyclic reapplication within
complex stem-level forms;
processes may be neutralizing or purely allophonic within
a stem-level process does display cyclic reapplication within
complex stem-level forms, then it cannot be purely allophonic in
minimal domains (Chung's Generalization);
turn, cyclic reapplication within stem-level forms shows
irregularities and exceptions of its own.
and  show that this syndrome can be explained on the assumption that
stem-level constructs are listed nonanalytically.
OT with stochastic ranking retains Gregory Guy's insights into the
effect of cyclicity on phonological variation.
t-deletion applies with greater frequency in mist
(where the [t] belongs to the stem) than in miss-ed (where
the [t] belongs to a word-level suffix) because mist meets the
conditions for t-deletion both at the stem and at the word
levels, whereas miss-ed only meets them at the word level:
OT enjoys privileged insight into those phenomena reflecting the
diachronic life cycle of phonological processes.
allophony of liquids in present-day English provides a good example.
Synchronic phonological processes reflecting early changes in a
diachronic trajectory of liquid lenition tend to apply in smaller
cyclic domains (at higher levels) than processes reflecting later
changes: , . For example, there are many English dialects in which
• r-lenition applies at the word level, and r-deletion
at the phrase level;
• l-darkening applies at the word level, and l-vocalization at the phrase level.
enables us to provide cogent answers to questions such as the rise
of r-intrusion  and the history of English phrasal
addition, Stratal OT illuminates the problems of lexical diffusion,
e.g.  and ,
and of secondary split .