Papers
[9], [13],
[17], and [7]
together provide an overall
conception of
the place of phonology in the
architecture of grammar, and of the interactions of phonology with the
lexicon, morphosyntax, and
phonetics.
The
classical modular feedforward architecture
Stratal
OT assumes a classical modular feedforward architecture of
grammar:
see [9] and [13]. In a grammatical architecture of
this sort,
morphology, phonology, and phonetics constitute separate modules,
each possessing its own proprietary set of representations:
-
morphology performs computations over morphs;
-
phonology performs computations
over
discrete phonological categories;
-
phonetics performs computations over continuous
articulatory and auditory parameters.
These three modules interact
serially: morphology precedes phonology within each cycle; all phonology
precedes all phonetics;
morphology and phonetics do not share an interface.
The
following sections discuss various implications of Stratal OT's
modular architecture.
Phonology
and morphology Item
[9] lays out a system of four hypotheses
regulating the modular interaction
between morphology and phonology: the
Four-Hypothesis Programme. This consists of the following four postulates:
-
The
Morph Integrity Hypothesis asserts that morphology selects and
inserts morphs as integral units, and does not have the power to operate directly upon
elements of phonological representation such as features, segments, nodes, or
association lines.
-
The
Indirect Reference Hypothesis asserts that phonological constraints other than those on prosodic
alignment cannot refer to morphosyntactic information.
The
Phonetic Interpretability Hypothesis asserts that output phonological representations do not contain diacritics of morphosyntactic
affiliation.
As
noted above, the Cycle Hypothesis asserts
that phonology applies cyclically over morphosyntactically
defined domains.
The Four Hypothesis
Programme establishes a clear modular demarcation between regular
phonology and suppletive allomorphy. This demarcation explains
key properties of phonological paradigmatic dependencies,
whose existence turns out to be fully compatible with a cyclic
approach to morphology-phonology interactions: see [17].
In
addition, the
Four-Hypothesis Programme entails an approach to nonconcatenative
morphology labelled Generalized Nonlinear Affixation. In this
view, the role of morphology in apparently
nonconcatenative exponence reduces to the insertion of morphs whose
phonological content is nonsegmental: i.e. floating pieces of
feature geometry or bare fragments of prosody. Item [9] works out the implications of Generalized Nonlinear Affixation for
the analysis of reduplication. Item [16]
provides a list of references to recent work in Generalized
Nonlinear Affixation.
Finally, the cycle
gives rise to a range of locality effects. Items [12] and [14] explore cyclic locality constraints on
outward-looking phonologically driven
allomorph selection.
In addition, the depth of morphosyntactic information
that phonology can access within a cyclic domain is restricted by Phonetic Interpretability:
thus, a form of inward
cyclic locality akin to ‘Bracket
Erasure’ emerges for free, as shown in [9].
Phonology
and the lexicon Stratal
OT bans lexically indexed constraints, and
also prohibits different cophonologies within the same level:
see [9] and [20]. As
noted above, these restrictions are crucial to maintaining a modular distinction
between regular phonology and suppletive allomorphy: see [19].
The distinction between regular phonology and suppletive allomorphy, in turn, explains key facts about the diachronic
behaviour of paradigmatic patterns: see
[17]. In
addition, items [9], [11],
and [18] distinguish between two types of lexical listing: complex
constructs may be
•
listed nonanalytically (as whole output forms) or
•
listed analytically (as concatenations
of input pieces).
These papers
argue that
stem-level constructs are
listed nonanalytically, whereas word-level constructs are either
unlisted or listed analytically. This postulate explains the
stem-level syndrome.
Finally, items
[12] and [14] demonstrate that, in a stratal-cyclic
architecture, the size of lexically listed exponents makes precise
predictions about locality conditions on phonologically driven
allomorph selection. The evidence of allomorphic locality
supports an approach to morphology that is stem-driven,
rather than root-driven. [12] and [14] describe
the format of lexical entries in this framework.
Phonology
and phonetics According
to the classical modular feedforward architecture assumed by Stratal
OT, processes of phonetic implementation refer exclusively to the
categorical phonological information contained in the output of the
phonological module, i.e. in surface
phonological representations; phonetics does not have direct access to
lexical information or to morphosyntactic structure. The predictions
of—and challenges to—this hypothesis are addressed in items [7],
[13],
and [15]. On
the one hand, the hypothesis that lexical representations consist of
discrete phonological categories and that phonetically gradient
properties are assigned by rule predicts the existence of neogrammarian
change: neogrammarian change is simply change in the rules of
phonetic implementation. See [13]
and [15]. On
the other hand, the modular feedforward architecture
appears to be challenged by two types of phenomena: •
apparent instances of morphologically conditioned phonetics, •
apparent instances of lexically specific phonetics. Items
[7]
and [13] show that the appearance
of morphologically conditioned phonetics can arise in at least two
ways, both of which are perfectly consistent with modularity:
-
In
some cases, morphological structure affects phonetic
implementation indirectly, through the categorical prosodic structure contained in the surface phonological
representation.
-
In
other cases, the appearance of morphologically conditioned
phonetics arises through rule scattering: i.e. though a
situation in which a categorical phonological process and the
gradient phonetic pattern from which it originates coexist
synchronically in the same grammar. Rule scattering is an
ordinary outcome of the diachronic
mechanism of stabilization whereby gradient
phonetic rules become categorical in the course of the life cycle of phonological processes.
Item
[15] addresses the problem of apparent
word-specific phonetics, which arises from the effects of gradient
usage-related factors (such as lexical token frequency and
neighbourhood density) on phonetic implementation. In Stratal OT,
frequency and neighbourhood density effects reflect gradient
symbolic activation: lexical representations consist solely of
discrete categories and are free of gradient phonetic detail, but
they exhibit continuously varying levels of activation. Activation
cascades downwards to the phonetic implementation module during
processing, giving rise to gradient effects. This approach to the
role of lexical token frequency correctly predicts the emergence of Constant
Rate Effects: as processes of lenition undergo phonetically
gradient incrementation diachronically, high-frequency words are
ahead of low-frequency words at every step of the change, but both
frequency groups change at the same rate.
The
life cycle of phonological processes
Research
in the tradition of Lexical Phonology
and Stratal OT pays close attention to the intimate connection
between the architecture of phonology and phonological change. In
particular, Stratal OT provides an insightful account of the life cycle of phonological
processes, surveyed in [3], [10],
and [13].
-
Mechanical
phonetic effects become phonologized as
language-specific gradient processes of phonetic implementation:
see [10],
[13].
-
Gradient
processes of phonetic implementation become stabilized as
categorical phonological processes applying across the board in
phrase-level domains:
see [10],
[13].
-
Through
so-called ‘analogical
change’,
operating by input restructuring, phonological processes undergo
domain narrowing, and so phonological generalizations
climb up from the phrase level to the word level and from the
word level to the stem level: see [10] and
[13], with further examples in [8]
and [12].
-
Phonological
rules eventually become morphologized or lexicalized:
see [9].
-
Each of the steps in
this pathway may produce rule scattering, whereby an
innovative avatar of an existing process enters a higher
component of the grammar whilst the old process remains in
situ: see [7],
[13].
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