A Constraint-based Approach to English Prosodic Constituents
Ewan Klein Division of Informatics University of Edinburgh 2 Buccleuch Place, Edinburgh EH8 9LW, UK [email protected]
Abstract in the sense that heads can be subcategorized with respect to the syntactic and semantic properties of The paper develops a constraint-based the- their arguments (i.e., their arguments’ synsem values), ory of prosodic phrasing and prominence, but not with respect to their arguments’ phonological basedonanHPSGframework,withan properties. Although I am not convinced that this implementation in ALE. Prominence and restriction is correct, it is worthwhile to explore what juncture are represented by n-ary branching kinds of phonological analyses are compatible with it. metrical trees. The general aim is to Most of the data used in this paper was drawn from define prosodic structures recursively, in the SOLE spoken corpus (Hitzeman et al., 1998).1 The parallel with the definition of syntactic corpus was based on recordings of one speaker reading structures. We address a number of prima approximately 40 short descriptive texts concerning facie problems arising from the discrepancy jewelry. between syntactic and prosodic structure 2 Syntactic and Prosodic Structure 1 Introduction 2.1 Metrical Trees This paper develops a declarative treatment of pros- Metrical trees were introduced by Liberman (1977) as odic constituents within the framework of constraint- a basis for formulating stress-assignment rules in both based phonology, as developed for example in (Bird, words and phrases. Syntactic constituents are assigned 1995; Mastroianni and Carpenter, 1994). On relative prosodic weight according to the following such an approach, phonological representations are rule: encoded with typed feature terms. In addition to the representational power of complex feature values, (1) NSR: In a configuration [C AB],ifC is a phrasal the inheritance hierarchy of types provides a flexible category, B is strong. mechanism for classifying linguistic structures, and for expressing generalizations by means of type Prominence is taken to be a relational notion: a inference. constituent labelled ‘s’ is stronger than its sister. To date, little work within constraint-based phono- Consequently, if B in (1) is strong, then A must be logy has addressed prosodic structure above the level weak. of the foot. In my treatment, I will adopt the following In the case of a tree like (2), Liberman and assumptions: Prince’s (1) yields a binary-branching structure of the kind illustrated in (3) (where the root of the tree is 1. Phonology is induced in parallel with syntactic unlabeled): structure, rather than being mapped from pre- built parse trees. (2) VP 2. Individual lexical items do not impose constraints on their neighbour’s phonology. NP
The first of these assumptions ensures that phonology V Det N is compositional, in the sense that the only information available when assembling the phonology of a com- fasten a cloak plex constituent is the phonology of that constituents 1The task of recovering relevant examples from the daughters. The second assumption is one that is SOLE corpus was considerably aided by the Gsearch corpus standardly adopted in HPSG (Pollard and Sag, 1994), query system (Corley et al., 1999).
(3) analysed into a sequence of elements of the next lower ¯ category (such as Phonological Phrase). However, it s is important to note that every IP will be a prosodic constituent, in my sense. Moreover, my lower-level w w s prosodic constituents could be identified with the ϕ-phrases of (Selkirk, 1981; Gee and Grosjean, 1983; fasten a cloak Nespor and Vogel, 1986; Bachenko and Fitzpatrick, 1990), which are grouped together to make IPs. For any given constituent analysed by a metrical tree t, the location of its main stress can be found by tracing 2.2 Representing Prosodic Structure a path from the root of t to a terminal element α such I shall follow standard assumptions in HPSG by that all nodes on that path are labelled ‘s’. Thus the separating the phonology attribute out from syntax- main stress in (3) is located on the element cloak.In semantics (SYNSEM):
general, the most prominent element, defined in this
# " way, is called the Designated Terminal Element (DTE) PHON pros
(Liberman and Prince, 1977). (4) feat-struc ! SYNSEM synsem Note that (1) is the metrical version of Chomsky and Halle’s (1968) Nuclear Stress Rule (NSR), and The type of value of PHON is pros (i.e., prosody). encodes the same claim, namely that in the default In this paper, I am going to take word forms as case, main stress falls on the last constituent in a phonologically simple. This means that the prosodic given phrase. Of course, it has often been argued that type of word forms will be maximal in the hierarchy. the notion of ‘default prominence’ is flawed, since it The only complex prosodic objects will be metrical supposes that the acceptability of utterances can be trees. The minimum requirements for these are that judged in a null context. Nevertheless, there is an we have, first, a way of representing nested prosodic alternative conception: the predictions of the NSR domains, and second, a way of marking the strong correctly describe the prominence patterns when the element (Designated Terminal Element; DTE) in a whole proposition expressed by the clause in question given domain. receives broad focus (Ladd, 1996). This is the view Before elaborating the prosodic signature further, that I will adopt. Although I will concentrate in I need to briefly address the prosodic status of the rest of the paper on the broad focus pattern of monosyllabic function words in English. Although intonation, the approach I develop is intended to link these are sometimes classified as clitics, Zwicky up eventually with pragmatic information about the (1982) proposes the term Leaners. These “form a location of narrow focus. rhythmic unit with the neighbouring material, are In the formulation above, (1) only applies to normally unstressed with respect to this material, and binary-branching constituents, and the question arises do not bear the intonational peak of the unit. English how non-binary branching constituent structures (e.g., articles, coordinating conjunctions, complementizers, for VPs headed by ditranstive verbs) should be treated. relative markers, and subject and object pronouns are One option (Beckman, 1986; Pierrehumbert and all leaners in this sense” (Zwicky, 1982, p5). Zwicky Beckman, 1988; Nespor and Vogel, 1986) would be takes pains to differentiate between Leaners and to drop the restriction that metrical trees are binary, clitics; the former combine with neighbours to form allowing structures such as Fig 1. Since the nested Phonological Phrases (with juncture characterized by structure which results from binary branching appears external sandhi), whereas clitics combine with their to be irrelevant to phonetic interpretation, I will use hosts to form Phonological Words (where juncture is n-ary metrical trees in the following analysis. characterized by internal sandhi). In this paper, I will not make use of the Pros- Since Leaners cannot bear intonational peaks, odic Hierarchy (Beckman and Pierrehumbert, 1986; they cannot act as the DTE of a metrical tree. Nespor and Vogel, 1986; Selkirk, 1981; Selkirk, Consequently, the value of the attribute DTE in a 1984). Most of the phenomena that I wish to deal metrical tree must be the type of all prosodic objects with lie in the blurry region (Shattuck-Hufnagel and which are not Leaners. I call this type full,and Turk, 1996) between the Phonological Word and it subsumes both Prosodic Words (of type p-wrd) the Intonational Phrase (IP), and I will just refer and metrical trees (of type mtr). Moreover, since to ‘prosodic constituents’ without committing myself Leaners form a closer juncture with their neighbours to a specific set of labels. I will also not adopt than Prosodic Words do, we distinguish two kinds the Strict Layer Hypothesis (Selkirk, 1984) which of metrical tree. In a tree of type full-mtr, all the holds that elements of a given prosodic category daughters are of type full, whereas in a tree of type (such as Intonational Phrase) must be exhaustively lnr-mtr, only the DTE is of type full. ¯
w s
w w s w w s
fasten the cloak at the collar Figure 1: Non-binary Metrical Tree
pros lnr full mtr p-wrd DOM: list(pros) DTE: full
lnr-mtr
full-mtr i DOM: list(lnr) ¨h1 DOM: list(full) DTE: 1
Figure 2: Prosodic Signature
¿ ¾
In terms of the attribute-value logic, we therefore sign
¾ ¿
7 6 7
postulate a type mtr of metrical tree which introduces 6 full-mtr
7 6
6 7
¾ ¿ 7
DOM 6 7
the feature (prosodic domain) whose value is a 6
7 6 ·
¶ full-mtr
6 7
7 6
D E
6 7 7
list of prosodic elements, and a feature DTE whose 6
7 6
6 7
6 7 7
6 PHON DOM fasten, 1 DOM 2 this, cloak
6 7
4 5 7
value is a full prosodic object: 6
6 7
7 6
6 7 7
6 DTE 2 " #
4 5 5 DOM 4 list(pros) DTE 1 (5) mtr ! DTE full Figure 3: Feature-based Encoding of a Metrical Tree Fig 2 displays the prosodic signature for the grammar. The types lnr-mtr and full-mtr specialise the appropriateness conditions on mtr, as discussed above. 3 Associating Prosody with Syntax Notice that in the constraint for objects of type lnr-mtr,
¨ is the operation of appending two lists. In this section, I will address the way in which Since elements of type pros can be word-forms prosodic constituents can be constructed in parallel or metrical trees, the DOM value in a mtr can, in with syntactic ones. There are two, orthogonal, principle, be a list whose elements range from simple dimensions to the discussion. The first is whether word-forms to lists of any level of embedding. One the syntactic construction in question is head-initial way of interpreting this is to say that DOM values or head-final. The second is whether any of the need not obey the Strict Layer Hypothesis (briefly constituents involved in the construction is a Leaner mentioned in Section 2.1 above). or not. I will take the first dimension as primary, and To illustrate, a sign whose phonology value introduce issues about Leaners as appropriate. corresponded to the metrical tree (6) (where the The approach which I will present has been word this receives narrow focus) would receive the implemented in ALE (Carpenter and Penn, 1999), and representation in Fig 3. although I will largely avoid presenting the rules in ALE notation, I have expressed the operations for (6) ¯ building prosodic structures so as to closely reflect the relational constraints encoded in the ALE grammar. s 3.1 Head-Initial Constructions w s w As far as head-initial constructions are concerned, fasten this cloak I will confine my attention to syntactic constituents which are assembled by means of HPSG’s Head-
¿ ¾
¾ ¿
phrase word
7 6 7
6 PHON ϕ 7 6
hϕ ; ϕ ;:::ϕ iµ
PHON ´ 0 7
6 mkMtr 0 1 n
! ::: 7
6 1 , , n
h h i h i i
4 5
5 4
hi ϕ ϕ SYNSEM COMPS COMPS 1 PHON 1 , ::: , n PHON 1
Figure 4: Head-Complement Rule
Complement Rule (Pollard and Sag, 1994), illustrated Examples of the prosody constructed for an N-bar in Fig 4. The ALE rendering of the rule is given in (7). and a VP are illustrated in (11)–(12). For convenience, (7) head_complement rule Iuse[of the samurai] to abbreviate the AVM (phrase, phon:MoPhon, representation of the metrical tree for of the samurai, synsem:(comps:[], and similarly for [a cloak]and[at the collar].
spr:S, i
head:Head)) (11) mkMtr( hpossession,[of the samurai] )= ¿ ===> ¾
cat> (word, phon:HdPhon, full-mtr
D E
6 7 7
synsem:(comps:Comps, 6 DOM possession, 1 [of the samurai] 5 spr:S, 4 head:Head)), DTE 1
cats> Comps, i
goal> (getPhon(Comps, PhonList), (12) mkMtr( hfasten,[a cloak], [at the collar] )= ¿ mkMtr([HdPhon|PhonList], MoPhon)). ¾
full-mtr
D E
6 7 7
6 DOM fasten,[a cloak], 1 [at the collar] 5 The function mkMtr (make metrical tree) (encoded 4 as a relational constraint in (7)) takes a list consisting DTE 1 of all the daughters’ phonologies and builds an Let’s now briefly consider the case of a weak appropriate prosodic object ϕ. As the name of the pronominal NP occurring within a VP. Zwicky function suggests, this prosodic object is, in the (1986) develops a prosodically-based account of the general case, a metrical tree. However, since metrical distribution of unaccented pronouns in English, as trees are relational (i.e., one node is stronger than the illustrated in the following contrasts: others), it makes no sense to construct a metrical tree if there is only a single daughter. In other words, if the (13) a. We took in the unhappy little mutt right head’s COMPS list is empty, then the argument mkMtr away. is a singleton list containing only the head’s PHON b.*We took in hˇim right away. value, and this is returned unaltered as the function ˇ value. c. We took him in right away.
(14) a. Martha told Noel the plot of Gravity’s i (8) mkMtr( h 1 [pros] )= 1 Rainbow. The general case requires at least the first two elements b.*Martha told Noel ˇit. on the list of prosodies to be of type full, and builds a ˇ tree of type full mtr. c. Martha told it to Noel.
Pronominal NPs can only form prosodic phrases in
::: i
(9) mkMtr( 1 h[full], [full], , 2 )= ¿ ¾ their own right if they bear accent; unaccented pro-
full-mtr nominals must combine with a host to be admissible. 7
6 1 5 4 DOM Zwicky’s constraints on when this combination can DTE 2 occur are as follows: Note that the domain of the output tree is the input (15) A personal pronoun NP can form a prosodic list, and the DTE is just the right-hand element of the phrase with a preceding prosodic host only if the domain. (10) shows the constraint in ALE notation; following conditions are satisfied: the relation rhd DTE/2 simply picks out the last element of the list L. a. the prosodic host and the pronominal NP are sisters; (10) mkMtr(([full, full|_], L), (full_mtr, dom:L, dte:X)) if b. the prosodic host is a lexical category; rhd_DTE(L, X). c. the prosodic host is a category that governs case marking.
¿ ¾
¾ ¿
phrase phrase
7 6 7
6 PHON ϕ 7 6
ϕ ; ϕ µ
PHON ´ 0 7
6 extMtr 1 0
! 7
1 6
h h i i
4 5 5 4 ϕ SYNSEM SPR hi SPR 1 PHON 1
Figure 5: Head-Specifier Rule
These considerations motivate a third clause to the 3.2 Head-Final Constructions definition of mkMtr: To illustrate head-final constructions, I will focus
on NP structures, considering the combination of i¨
(16) mkMtr( h 1 [p-wrd], 2 [lnr] 3 )= ¾
¿ determiners and prenominal adjectives with N-bar
h i
mkMtr( lnr-mtr ¨ 3 ) phrases. I take the general case to be illustrated by
6 7 i
h 1 2 4 DOM , 5 combining a determiner like this with a phrase like DTE 1 treasured possession to form one metrical tree. Since treasured possession will itself be a metrical tree, I That is, if the first two elements of the list are a introduce a new, binary, function for this purpose, Prosodic Word and a Leaner, then the two of them namely extMtr (extend metrical tree) which adds a combine to form a lnr-mtr, followed by any other new prosodic element to the left boundary of an material on the input list. Because of the way in existing tree. For convenience, I will call the leftmost which this prosodic constraint is associated with the argument of extMtr the extender. Head-Complement Rule, the prosodic host in (16), Fig 5 illustrates the way in which extMtr is used namely the p-wrd tagged 1 , is automatically the to build the prosody of a specifier-head construction, syntactic head of the construction. As a result, while (19) provides the definition of extMtr.An Zwicky’s conditions in (15) fall out directly. example of the output is illustrated in (20).
(17)–(18) illustrate the effects of the new clause. In
" # the first case, the lnr-mtr consisting of told and it is the DOM 2 (19) extMtr( 1 [full], )= only item on the list in the recursive call to mkMtr in DTE 3
(16), and hence the base clause (8) in the definition of
¾ ¿
mkMtr applies. In the second case, there is more than full-mtr
6 7
one item on the list, and the lnr-mtr becomes a subtree 1 ¨ 2 5 4 DOM in a larger metrical domain. DTE 3 (17) mkMtr([told, it]) =
(20) extMtr(this,[treasured possession]) =
¾ ¿
¾ ¿
lnr-mtr full-mtr
D E
6 7
D E
6 7 7
6 DOM 1 told, it
6 7 5
4 DOM this, treasured, 1 possession
4 5 DTE 1 DTE 1
(18) mkMtr([told, it,[to Noel]]) = ¿ ¾ However, there are now a number of special cases
full-mtr
7 6 to be considered. First, we have to allow that the head
¿ ¾
6 7 ·
¶ lnr-mtr 7
6 phrase is a single Prosodic Word such as possession,
D E
7 6
6 7
7 6 7
6 DOM DOM 1 told, it 2 [to Noel] rather than a metrical tree. Second, the prosodic
6 7
5 4 7
6 structure to be built will be more complex if the head 7
6 DTE 1 5 4 phrase itself contains a post-head complement, as in DTE 2 treasured possession of the samurai. Crosscutting this dimension is the question of whether the extender is a By contrast, examples of the form told Noel itˇ fail to Leaner, in which case it will form a lnr-mtr with the parse, since (16) only licenses a head-initial lnr-mtr immediately following element. We will look at these when the Leaner immediately follows the head. We cases in turn. could however admit told Noel it´ , if the lexicon contained a suitable entry for accent-bearing it´ with (i) The head is a single Prosodic Word When the prosody of type p wrd, since this would satisfy the second prosodic argument of extMtr is not in fact a requirement that only prosodies of type full can be the metrical tree, it calls mkMtr to build a new metrical value of a metrical tree’s DTE. tree. Definition (21) is illustrated in (22).
¾ ¿
NP full-mtr
6 7
Det Nom 1 2 ¨ 3 5 4 DOM extMtr( , )
the AdjP Nom DTE 4
N PP provided that 2 is the lexical head.
most treasured ¿
possession P NP ¾full-mtr
D E
6 7 7
of (24) extMtr(this, 6 DOM possession, 1 [of the samurai] )= 5 the samurai 4
DTE 1
¾ ¿
Figure 6: Right-branching NP Structure full-mtr
6 ¾ ¿ 7
D E
¶ ·
6 7
¯ 7
6 DOM this, 2 possession
6 7 5
DOM 4 , 1 [of the samurai]
6 7 7
w s 6 DTE 2
4 5 DTE 1 w w s
the most treasuredpossession of the samurai Turning back briefly to the Head-Specifier Rule shown in Fig 5, we can now see that if ϕ0 is a metrical Figure 7: Flat NP Prosodic Structure ϕ tree M, then the value of extMtr(ϕ1 ; 0) depends on the syntactic information associated with the leftmost (21) extMtr( 1 [pros], 2 [p-wrd]) = element P of that tree. That is, if P is the phonology
of the lexical head of the phrase, then it can be i mkMtr( h 1 , 2 ) prosodically disjoined from the following material,
(22) extMtr(treasured, possession)= otherwise the metrical tree M is extended in the ¿ ¾ standard way.
full-mtr There are various ways that this sensitivity to
D E
6 7 7
6 DOM treasured, 1 possession syntactic role might be accommodated. One option 5 4 would to inspect the DTRS (daughters) attribute of a DTE 1 sign. However, I will briefly sketch the treatment implemented in the ALE grammar, which does not (ii) The head contains post-head material Perhaps build a representation of daughters. Instead, I have the most awkward kind of mismatch between syntactic introduced an attribute LEX inside the value of HEAD and prosodic structure arises when when the comple- which is constrained in the case of lexical items to be ment or postmodifier of a syntactic head is ‘promoted’ token-identical to the PHON value. For example, the to the level of sister of the constituent in which the type for possession is approximately as follows:
head occurs; this creates a disjuncture between the
¿ ¾
lexical head and whatever follows. Fig 6 gives a (25) word 7
typical example of this phenomenon, where the noun 6 1 7
6 PHON possession
¾ ¿
7 6 #
possession is followed by a prepositional complement, "
7 6 7
while Fig 7 represents the prosodic constituency. 6 noun
6 7
7 6
SYN j HEAD
6 7 7
Let’s consider how treasured should combine with 6 SYNSEM LEX 1
4 5
5 4
possession of the samurai. The Head-Complement i ARG-ST hPP Rule will have built a prosodic structure of the form [possession [of the samurai]] for the latter phrase. To Since LEX is a head feature, it percolates up to obtain the correct results, we need to be able to detect any phrase projected from that head, and allows the that this is a metrical tree M whose leftmost element PHON value of the lexical head to be accessed at is a lexical head (by contrast, for example, with the that projection; i.e., headed phrases will also bear a structure [treasured possession]). In just this case, the specification [LEX phon], which can be interpreted as extender can not only extend M but also create a new saying “my lexical head’s phonology value is phon”. subtree by left-associating with the lexical head.2 The In addition, we let the function extMtr in Fig 5 take as required definition is shown in (23) and illustrated in an extra argument the HEAD value of the mother, and
example (24). then test whether the leftmost Prosodic Word in the # " metrical tree being extended is the same as the LEX
DOM 2 p-wrd ¨ 3 (23) extMtr( 1 [full], )= value of the mother’s HEAD value. DTE 4 (iii) Extending the head with a Leaner Finally, 2The special prosodic status of lexical heads is incorpor- ated in Selkirk’s (1981) notion of ϕ-phrase, and subsequent there is an additional clause to accommodate the developments thereof, such as (Selkirk, 1986; Nespor and case where the extending element is a Leaner. This Vogel, 1986). triggers a kind of left association, in that the result of combining a with [treasured possession]isastructure There are numerous directions in which the current
of the form [[a treasured] possession]. work can be extended. In terms of empirical coverage, #
" a more detailed account of weak function words i¨ (26) extMtr( 1 [lnr], h 2 3 )= DOM seems highly desirable. The approach can also
DTE 4 be tested within the context of speech synthesis,
¾ ¿
full-mtr and preliminary work is underway on extending the 7 6 Festival system (Black and Taylor, 1997) to accept
1 2 ¨ 3 5 4 DOM extMtr( , ) input text marked up with metrical trees of the kind DTE 4 presented here. In the longer term, the intention is to This will also allow an unaccented subject pronoun integrate prosodic realisation within the framework of to left-associate with the lexical head of a VP, as in an HPSG-based concept-to-speech system. [[he provoked][the objections of everyone]] (Gee and Grosjean, 1983). Acknowledgements 4 Concluding Remarks I am grateful to Philip Miller, Mike Reape, Ivan Sag and Paul Taylor for their helpful comments on various I believe that the preceding analysis demonstrates that incarnations of the work reported here. despite the well-known mismatches between syntactic and prosodic structure, it is possible to induce the required prosodic structures in tandem with syntax. References Moreover, the analysis retains rather conventional notions of syntactic constituency, eschewing the non- J. Bachenko and E. Fitzpatrick. 1990. A com- standard syntactic constituents advocated by Prevost putational grammar of discourse-neutral prosodic phrasing in English. Computational Linguistics, and Steedman (1993), Steedman (1990; 1991). 16(3):155–170. Although I have only mentioned two syntactic rules in HPSG, the radically underspecified nature of these Mary E. Beckman and Janet B. Pierrehumbert. 1986. rules, coupled with rich lexical entries, means that the Intonational structure in English and Japanese. approach I have sketched has more generality than Phonology Yearbook, 3:255–310. might appear at first. With the addition of a rule for prenominal adjectives, prosodically interpreted Mary E. Beckman. 1986. Stress and Non-Stress like the Head-Specifier Rule, we can derive a range Accent. Foris, Dordrecht, Holland. of analyses as summarised in (27). Here, I use Steven Bird. 1995. Computational Phonology: A square brackets to demarcate trees of type full-mtr and Constraint-Based Approach. Studies in Natural parentheses for trees of type lnr-mtr. Language Processing. Cambridge University Press. (27) a. [this possession](of the samurai) Alan W. Black and Paul Taylor. 1997. The b. [this treasured possession](of the samurai) festival speech synthesis system. Technical Report c. (a treasured) possession TR-83, Human Communication Research Centre, d. (a treasured) possession [(of these) people] University of Edinburgh, Edinburgh, UK, January. e. Kim gave (the book) (to the boy) Bob Carpenter and Gerald Penn, 1999. ALE: f. Kim (gave it) (to the boy) The Attribute Logic Engine. User’s Guide.Bell g. Kim is happy [about Lee] Laboratories, Lucent Technologies, Murray Hill, h. Kim is happy [(that Lee) is fond (of the bird)] NJ, version 3.2 beta edition. i. Kim wanted (to rely) (on the report) [(that Lee) is fond (of the bird)] Noam Chomsky and Morris Halle. 1968. The Sound Pattern of English. Harper and Row, New York. It would be straightforward to augment the grammar to accommodate post-modifiers of various kinds, Steffan Corley, Martin Corley, Frank Keller, Mat- which would behave prosodically like post-head thew W. Crocker, and Shari Trewin. 1999. complements. By contrast, auxiliaries do not conform Finding syntactic structure in unparsed corpora: The gsearch corpus query system. Computers and to the association between headed structures and the Humanities. prosodic structures that we have seen so far. That is, if auxiliaries are a subtype of complement-taking verbs, James Paul Gee and Franc¸ois Grosjean. 1983. as assumed within HPSG, then they depart from the Performance structures: a psycholinguistic and usual pattern in behaving prosodically like specifiers linguistic appraisal. Cognitive Psychology, 15:411– rather than heads. 458. Janet Hitzeman, Alan W. Black, Paul Taylor, Chris Mark Steedman. 1991. Structure and intonation. Mellish, and Jon Oberlander. 1998. On the use Language, 67(2):260–296, June. of automatically generated discourse-level inform- ation in a concept-to-speech synthesis system. In Arnold M. Zwicky. 1982. Stranded to and ICSLP’98, pages 2763–2768. phonological phrasing in English. Linguistics, 20(1/2):3–57. D. Robert Ladd. 1996. Intonational Phonology. Cambridge University Press, Cambridge. Arnold M. Zwicky. 1986. The unaccented pronoun constraint in English. In Arnold M. Zwicky, editor, Mark Liberman and Alan Prince. 1977. On stress and Interfaces, volume 32 of Ohio State University linguistic rhythm. Linguistic Inquiry, 8:249–336. Working Papers in Linguistics, pages 100–114. Ohio State University Department of Linguistics, Michael Mastroianni and Bob Carpenter. 1994. July. Constraint-based morpho-phonology. In Proceed- ings of the First ACL SIGPhon Workshop,Los Cruces, New Mexico. Association for Computa- tional Linguistics.
Marina Nespor and Irene Vogel. 1986. Prosodic Phonology. Number 28 in Studies in Generative Grammar. Foris Publications, Dordrecht.
Janet B. Pierrehumbert and Mary E. Beckman. 1988. Japanese Tone Structure. Number 15 in Linguistic Inquiry Monographs. The MIT Press, Cambridge, MA. Carl Pollard and Ivan A. Sag. 1994. Head-Driven Phrase Structure Grammar. CSLI and University of Chicago Press, Stanford, Ca. and Chicago, Ill.
Scott Prevost and Mark Steedman. 1993. Generating contextually appropriate intonation. In Proceedings of the 6th Conference of the European Chapter of the Association for Computational Linguistics, pages 332–340, Utrecht, The Netherlands, April 21–23. OTS (The Research Institute for Language and Speech).
Elisabeth Selkirk. 1981. On prosodic structure and its relation to syntactic structure. In T. Fretheim, ed- itor, Nordic Prosody II: Papers from a Symposium. Tapir, Trondheim. Elisabeth O. Selkirk. 1984. Phonology and Syntax: The Relation between Sound and Structure. Current Studies in Linguistics. MIT Press, Cambridge, Mass.
Elisabeth O. Selkirk. 1986. On derived domains in sentence phonology. Phonology Yearbook, 3:371– 405. Stefanie Shattuck-Hufnagel and Alice E. Turk. 1996. A prosody tutorial for investigators of auditory sentence processing. Journal of Psycholinguistic Research, 25(2):193–247. Mark Steedman. 1990. Intonation and structure in spoken language understanding. In Proceedings of the 28th Annual Meeting of the Association for Computational Linguistics, pages 9–16, Pittsburgh, Pa., June. University of Pittsburgh.