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<Paper uid="E91-1023">
  <Title>PROSODIC INHERITANCE AND MORPHOLOGICAL GENERALISATIONS</Title>
  <Section position="4" start_page="0" end_page="0" type="metho">
    <SectionTitle>
2. INHERITANCE AND NON-CONCATENATIVE
MORPHOLOGY
</SectionTitle>
    <Paragraph position="0"> Morphological generalisations are of three basic kinds: morphotactic, the combinatorial principles of word composition in terms of immediate dominance (ID) relations, morphosemantic, interpretation functions from morphotactic structures to semantic representations, and morphophonologica/ ( or ' morphograph ic') , interpretation functions from morphotactic structures to surface phonological or orthographic representations. This paper is mainly concerned with modelling morphotactic and morphophonological generalisations.</Paragraph>
    <Paragraph position="1"> Simple abstract morphotactic combinations (denoted by the operator '*') may be represented as follows: Ger.: \[Rad * singular\], \[Rad * plural\] Eng.: \[cat * plural\], \[dog * plural\], \[horse * plural\] Morpheme ID combinations receive a compositional morphophonological interpretation based on the forms of the component morphemes and the kind of construction involved. Phonological interpretations are composed primarily by means of concatenation, with phonological feature variation at morpheme boundaries: Get.: Rad-Rades,/ra:t/-/ra:des/ (Voicing specification of stem final C) Eng.: cats-dogs-horses,/keets/-/dogz/-/ho:siz/ (Voicing specification of C and epenthetic V in suffix) Non-concatenative morphophonological composition (which we will here refer to as morphoprosody) deals specifically with temporal feature overlap phenomena such as infixing, vowel gradation, consonant mutation, morphological tone and stress patterning, involving the structural 'association' of temporally coextensive categories such as features and autosegmental tiers: Eng.: telephone, telephony, telephonic (stress, vowel quality) Ger.: Fuchs, F~ichse, fuchsig (Umlaut) Arab.: ktb, kutib, aktabib (intercalation) Kikuyu: hmahmolrorlihra, hmahmoltomhihre (tone) Morphoprosodic operations generally occur in combination with concatenation. Concatenation and association operators ('quasi-linear precedence, QLP, operators') are represented here - 131 by &amp;quot; and ,o, respectively. QLP representations are intermediate specifications of morphotactic detail between abstract ID and concrete phonological representations.</Paragraph>
    <Paragraph position="2"> Morphophonological generalisations thus require three levels of abstraction:</Paragraph>
    <Paragraph position="4"> Details of phonological feature structure will not be dealt with here.</Paragraph>
    <Paragraph position="5"> The only explicit computational treatment of association operations is by Kay (1987; but cf. also the formal account by Bird &amp; Klein, 1990), who models autosegmental phonological association with a multi-tape finite state transducer. Like autosegmental descriptions, Kay's finite state tranducers explicitly operate with directional (leff-to-right or right-to-left) algorithms. Other approaches rely on lists of stem variants, string permutations, or string position indices (Cahill 1990).</Paragraph>
    <Paragraph position="6"> By contrast, the Pi approach to morphoprosody does not rely on algorithmic conditions such as leff-right rule application, but on a general default principle: Assign a default value everywhere in a given context unless a) a designated value, and b) a designated position are otherwise specified in an explicit constraint. E.g. Get.: Assign non-umlaut everywhere in a stem unless a) an umlauting stem, and b) an umlaut-triggering affix cooccur.</Paragraph>
    <Paragraph position="7"> Arab.: Assign the default vowel of a vocalism (default consonant of a radical) everywhere in a word unless a) a designated vowel (designated consonant), and b) a designated position in stem syllable structure are explicitly specified.</Paragraph>
    <Paragraph position="8"> In the PI approach, lexemes are treated as individual (or 'most specific') nodes in an inheritance net. They are underspecified and inherit their full representations from semantic, syntactic, and phonological default inheritance hierarchies. Each node in these hierarchies represents a morphophonological generalisation and is associated with a set of special cases (relative exceptions) over which a default priority ordering in terms of relative specificity is defined. Fully specified phonological and orthographic lexeme representations are inherited from a hierarchy of general templates representing word, syllable and segment structures, and marked with QLP operators. The template slots are instantiated with properties inherited from specific lexemes. In the DATR implementation, inheritance of representations is implemented by local inheritance, and inheritance of specific exceptions and template instantiations is implemented by global inheritance,</Paragraph>
  </Section>
  <Section position="5" start_page="0" end_page="0" type="metho">
    <SectionTitle>
. MORPHOLOGICAL GENERAUSATIONS:
UMLAUT AND INTERCALATION
</SectionTitle>
    <Paragraph position="0"> Two superficially related cases of non-concatenative morphology are Umlaut in German and vowel-consonant-intercalation in Arabic. They are similar in respect of the QLP operation of stem vowel variation in different morphological contexts, though the Arabic case is more complex, with additional variation of syllable structure and consonant position; in German, Umlaut primarily affects the vowel fronting feature.</Paragraph>
    <Paragraph position="1"> 3.1. GERMAN UMLAUT Current computational descriptions of German vowel fronting (Umlaut) are linguistically inadequate, in that they do not take into account the complexity of mutual conditioning between stem classes and inflectional and derivational affixes: either they ignore the complexities of derivational morphology (Schiller &amp; Steffens 1990), or overgeneralise, with lists of absolute exceptions Frost t990).</Paragraph>
    <Paragraph position="2"> In the PI model of German Umlaut, a wide range of 'exceptions' turn out to be important subregularities. The inflectional properties of stems are taken as defaults for both inflection and derivation; and captured in an inheritance hierarchy. Lexemes inherit fully specified stem forms, inflectional and derivational affixes, and Umlaut specification, via this hierarchy. The hierarchy for nouns specifies that Umlaut with zero-suffix plurals depends on gender, is arbitrarily specified for each lexeme with e-suffix plurals (Umlaut being the default case), always occurs with er-suffix plurals, never with e._nn-, s-, and exotic plurals. Derivational suffixes are also specified for their Umlaut-triggering properties, but different subregularities hold for different derivational suffixes in non-default cases.</Paragraph>
    <Paragraph position="3"> stem p!ur. infl, -isch deriv. -ig deriv, Fuchs Fi.ichs-e_ fi.ichs-isch fuchs-i.q.</Paragraph>
    <Paragraph position="4"> Hund Hund-e_ h/.ind-isch hund-i.q Consequently, Umlaut conditions must be inherited from several sources.</Paragraph>
    <Paragraph position="5"> The three levels of morphophonological generalisation for an umlauted plural form like F(jchse have the following representations: L 1 , Morphotactic ID: \[Fuchs * Plural\] L 2, Morphotactic QLP: \[\[Fuchs deg Umlaut\] ^ e\] L 3, Phonological: /f Y k s @/ Orthographic: &amp;quot;fi~chse&amp;quot; The DATR implementation fragment shown below can be interpreted fairly straightforwardly as a representation of a semantic inheritance net, in which the 'most specific' node is Fuchs, which has some typed properties of its own and inherits others via NounE. Queries specify a - 132 starting node and an attribute path. The left hand side of an equation is required to match a prefix of the query path; if there is more than one match for a node, the longest matching path overrides any others. Inheritance from more general nodes on the right hand side of an equation is explicitly constrained by associating them with a path. This path replaces the matching prefix of the query path in any further inheritance. If node or path are not specified, the node or path from the current local (or global) query environment is transferred.</Paragraph>
    <Paragraph position="6"> In this implementation, the lexeme .Fuchs inherits a full morphologically conditioned phonological/orthographic representation. In the lexical representation of Fuchs, the vowel is not specified for orthographic or phonological Umlaut. The vowel representation is inherited from a template with a vowel slot which conditionally inherits a \[+ umlaut\] or \[- umlaut\] morphological subcategory by multiple inheritance from the stem and affix concerned. The condition is implemented in DATR as nested inheritance: e.g. Voweh&lt;orth&gt; = = &lt;Plur:&lt;stem cond&gt; &gt; which conditionally specifies either Vowel: &lt; orth * = = &lt; \[ + umlaut\] &gt; or Vowel: &lt; orth &gt; = = &lt; \[-umlaut\] * depending on the value of Plur: &lt;stem cond&gt; for the lexeme concerned.</Paragraph>
    <Paragraph position="7"> A fragment of the PI implementation in DATR is stated below.</Paragraph>
    <Paragraph position="8"> Fuchs:</Paragraph>
    <Paragraph position="10"> &lt;orth flex plur surf op&gt; = = e surf.</Paragraph>
    <Paragraph position="11"> Noun:</Paragraph>
    <Paragraph position="13"> Typical PI mappings in DATR notation arf~: , Fuchs:&lt;orth infl plur&gt; = (F iJ c h s e).</Paragraph>
    <Paragraph position="14"> Fuchs:&lt;orth deriv ig-af* = (f u c h.s i g).</Paragraph>
    <Paragraph position="15"> A detailed account of the linguistic basis for the PI Umlaut model and the DATR implementation are given in Reinhard (1990a, 1990b).</Paragraph>
  </Section>
  <Section position="6" start_page="0" end_page="0" type="metho">
    <SectionTitle>
3.2. INTERCALATION IN ARABIC VERB
MORPHOLOGY
</SectionTitle>
    <Paragraph position="0"> A number of linguistic descriptions and computational implementations have treated various aspects of Arabic verb conjugation (McCarthy 1982, Hudson 1984, Kay 1987, Calder 1989, Cahill 1990, Bird 1990, Gibbon 1990).</Paragraph>
    <Paragraph position="1"> The full range of generalisations is dealt with in the PI model in an integrated morphological hierarchy, which is shown in the feature structure in Figure 1. The generalisations cover stem type (CV-skeleton) exceptions and subregularities, interactions between different morphological categories, and the relations between intercalation, prefixation and suffixation. null Arabic morphology has an agglutinative (concatenative) verb inflectional structure (cf. Table 1). It is combined with a radical (consisting only of consonants) and a vocalism (determined by three morphological categories: aspect, voice, and stem type) which are both intercalated in complex consonant-vowel skeletons, which are themselves derivational morphemes (cf. the DATR theorems in Table 2).</Paragraph>
    <Paragraph position="2"> These different stem types in Arabic verb morphology modify the meaning of the radical in partially predictable ways (e.g. as causative, reflexive). Morphophonological intercalation involves association of marked vowels and consonants to fixed skeleton positions, and &amp;quot;spreading&amp;quot; of the initial vowel and the final consonant, e.g. imperfective active in stem type xi: \[qtl deg &lt;a,i&gt; deg VCCWCVC\] = &amp;quot;aqtaalil&amp;quot;. Spreading is represented in feature structures by coindexing, and is implemented in DATR by treating the spreading vowel and consonant as defaults.</Paragraph>
    <Paragraph position="3"> The categories involved in a word like vanoatilna with radical g~, as in yanqatilna min halaaU al-harbi 'they (fern) are being killed in tile war', are: 3-pers, pl-num, fem-gen circumfix (PNG): y ... na Aspectual prefix: default V Stem type prefix: n Aspect/voice/stem type vocalism (Voc): &lt;a,i&gt; Reflexive stem type, vii (Skel): C V C V C Radical consOnantism 'kill' (Cons): qtl - 133 Thus the morphological generalisations are the following:</Paragraph>
    <Paragraph position="5"> The fully specified representation for vanaatilnal at level 2 is shown in a conventional feature notation in Figure 1. The attribute &amp;quot;surf = (= &amp;quot;surface&amp;quot;) subsumes phonology and orthography.</Paragraph>
    <Paragraph position="6"> The QLP operators of concatenation and asso.</Paragraph>
    <Paragraph position="7"> clation are represented by Prefix and Suffix attributes and by re-entrancy indexing, respectively. null  xv *qtunliy. xv *uqtanlay.</Paragraph>
    <Paragraph position="8"> Dhrj: &lt; perf act surf orth roman &gt; = Dhrj: &lt; imperf act surf orth roman &gt; = qi dahraj qi udahrij qii tadahraj qii atadahraj qiii d h a n r a j qiii a d h a n r i j qiv dharjaj, qiv adharjij.</Paragraph>
    <Paragraph position="9"> Dhrj: &lt; perf pass surf orth roman &gt; = Dhrj: &lt; Imperf pass surf orth roman &gt; = qi duhrij qi udahraj qi t u d u h rij qii u tad ah raj qiii d h u n r i j qiii u d h a n r aj qiv dhurjij, qiv udharjaj.</Paragraph>
    <Paragraph position="10">  qiv mudharjaj.</Paragraph>
    <Paragraph position="11"> PI-mapping in DATR for all Arabic triliteral and quadriliteral verb stem types for radicals g~J ('to kill') and dhrj ('to roll'). (Asterisks denote overgenerated unacceptable forms; unacceptability is due to morphophonological Irregularity in stem type i and to semantic subreguladties in the other stem types. Idiosyncratic unacceptability is not marked.) The compact lexeme representation in DATR notation is simply the following:</Paragraph>
    <Paragraph position="13"> The default root consonant (in this example T) spreads over all C positions in skeleton constituents which are unspecified for C 1 or C 2 radical tional class: consonants (e.g. in CVCVC, stem type vii, only Aspect_prefix; the last consonant). The main generalisations &lt; &gt; about the skeleton template hierarchy are shown &lt;lmperf&gt; in the following excerpt from the DATR imple- &lt;part&gt; mentation (note the resemblance to context-free phrase structure rules; the concatenation opera- Stemtype_prefix: tion is implicit in DATR list ordering): &lt; &gt; : = 0 &lt;iv&gt;</Paragraph>
    <Paragraph position="15"> Syllable templates with morphotactic conditions for derivationel class and instantiation from global root node: Firstsyllable:</Paragraph>
    <Paragraph position="17"> All other information about morphological composition and phonological QLP and feature structure is predictable, and derived from constituent node constraints. Coverage of the verb system is fairly complete, with all 15 triliteral and 4 quadriliteral stem types, including subregularities, stem type and aspect prefixes, and other inflectional prefixes and suffixes for person, number and gender.</Paragraph>
  </Section>
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