ProSynth 2.5

Some thoughts from York.

What we want to do in this document is to set out what we know about lists and appositions; we hope that this will be useful to everyone in seeing what the proposed structures are that we plan to work on. We’re also including as many references as we can, which we hope will help in rewriting the background.

We’ve had a bit of a brainstorm, and tried to come up with ideas that we hope will be helpful to everyone. Our feeling at the moment is that our proposal in ProSynth 2.4 is rather thin, and we need to find ways to develop it. John and I have the feeling that we can’t make a very convincing case at the moment for taking on six PIs and perhaps three RAs to do this work. On the other hand, we think if we set out much more clearly what our research programme is (hypotheses, materials, tests, etc.) then we might have a better case to make to EPSRC.

I’ve tried to set it out in under the headings we will eventually need, but some of this is too speculative for that at the moment. I’ve also put, in boldface and without a line in between, a line saying what each paragraph is about. (Might help with editing later.)

Gaps we are aware of.
There’s several gaps here. Firstly, we haven’t referred to enough of the intonation literature. We’re just not familiar enough with eg. work at IPO or Bob Ladd’s work. We hope JH can do that bit. Secondly, we haven’t written anything about hypo- and hyper-speech, for pretty much the same reasons. Thirdly, we’ve done something on finding out about the situation in TTS, but there’s still more we could do. We suggest that Jill should write something more about intonation and Sarah something more about hypo- and hyper-speech, if you see this as an important part of the proposal. We have said nothing about given and new. It’s deliberate. We think that there’s so much out there written about it that we don’t know that we’ll look foolish if we even try; and we at York anyway don’t think that it really helps us to conceptualise we we want to do because it’s rather informal. Do you want to persuade us otherwise?

Commentary in italics.

Filename: ProSynth 2.5
Date: 24 Nov 00
Author: Richard
Working from: notes we made here. This document doesn’t contain material from ProSynth 2.4; later versions of ProSynth 2.X perhaps will.

1. BACKGROUND.

1.1Some problems of prosody for TTS systems. (Monaghan 1999)
RAO finds these helpful: they set out the problems succinctly, and since they are not our opinions, but are those of someone well established in the TTS world, I would hope  they carry some weight. It seems to me that the solutions identified have many resonances with our work, and some of the later comments pertinent to diphone synthesis might help us to argue the relevance of our work too. If you agree that they are a useful thing to refer to (even in some detail?) please think about how to integrate them into our text.

Rhythm.
Problem. Synthetic speech has rhythm that is too regular; it is difficult to follow.
Solution. Better phrasing; co-ordination of rhythm across constituents of a phrase; linguistically-motivated adjustments to tempo across phrases. There are also interactions between articulatory parameters and rhythm which are not well understood.

Focus and deaccenting. 
Problem. TTS typically produce ‘neutral’ readings of texts where all information is given equal accentuation. This makes it confusing to the listener. 
Solution. Some prior discourse-based mark-up is necessary to make it possible to decide what to accent.

Pitch patterns.
Problems. Accents may be wrongly located; systems use and impoverished inventory of pitch accents, making synthetic speech monotonous; the phonetic realisation of pitch accents may be unnatural in alignment with the rest of the speech.
Solution. Use discourse knowledge. Model allowable variability (which relies on some notion of ‘sameness’); gain a better knowledge of the interaction between f0 and other phonetic parameters.

Segmental timing.
Problem. The timing of syllable units often seems disjointed. This destroys the percept of fluent rhythm.
Solution. Relate timing to the prosody of larger structures. The best solution is to use material with well understood metrical properties, which allows regularities to be modelled at different levels in the hierarchy.

Coarticulation on different scales.
Problem. Diphone and polyphone concatenation systems limit the extent to which segments can affect one another, producing speech which lacks phonetic coherence. Concatenation of larger units is not possible because of the sparsity of training data.
Solution. Use a metrical framework to express coarticulatory interactions over larger domains. Identify phonetic properties which pertain to structures rather than to segments.

Quality changes due to prosody.
Problem. Units are concatenated in current systems without making changes to segments consequent upon changing prosodic factors. Affects voice quality, resonance quality, vowel quality.
Solution. Research models of how segmental quality and voice quality change as a function of rate and pitch.
1.2 Information structure.

It is generally agreed that structural and functional categories are the major determinants of prosody (XX REFS NEEDED PLEASE). In order to generate natural-sounding prosody for synthetic speech, a detailed knowledge of syntax, semantics, pragmatics and discourse structure is needed. Monaghan (1999) suggests that there are two questions which need to be addressed:
•	What is the information that synthetic prosody should convey?
•	What are the phonetic correlates that will convey it?
Monaghan says that IPO are working on ‘pitch range phenomena and the interaction between the thematic structure of the discourse and turn-taking’. Turn-taking isn’t important to our project but thematic structure is. Would Jill be interested in checking this out?
1.3 Our use and understanding of the term ‘Prosody’

Much discourse information is made available to listeners through the ‘prosodic’ organisation of speech, where we understand ‘prosodic’ in a wider sense than merely ‘intonation’. Our understanding of the word is a broader one. We use it to refer to any phonetic parameters which hold a piece of speech together as such and make it ‘coherent’ (Hawkins 1995). This means that we consider any of the following phonetic parameters as potentially prosodic: pitch; tempo; rhythm; voice quality; segmental detail (especially secondary resonance and coarticulatory properties); and we consider the interaction between these things to be crucial in making speech perceptually coherent.

Much recent work has concentrated on the intonational or temporal aspects of speech., while for most other parameters we consider prosodic there is a considerably smaller body of research in the context of speech synthesis. Most work, moreover, treats each parameter separately, so that integration of prosodic factors is rarely achieved.

1.4 Target texts.

We think that getting the texts right is vital. We think that it’s important to show a practical slant to our work. So we suggest the following:
1.	Texts from on-line  newspapers like The Guardian and the Financial Times. The advantage is that these texts are independent of us, and there are new ones every day.
2.	The same kind of text from any source, eg. business news.
3.	The sort of text that people would want to have read, eg. a blind user of a web browser.
4.	Newspapers package information in particular ways. It may be that this generalises to other types of text such as dictionary entries or texts on eg. museum websites.
5.	We don’t see that this prevents us from adding more material, but we think that we can use texts like these to justify our project.
6.	WE NEED TO WORK OUT THE FREQUENCY OF THE KIND OF STRUCTURE WE’RE PROPOSING TO LOOK AT IN OUR TARGET TEXTS. 

1.5 Labelling
This is another issue we need to work out more carefully. We imagine we need at least: prosodic hierarchy labels; discourse labels (PRE, POST, APPOSITION, LIST ITEM + WHERE-IN-LIST). 

1.6 Information structure.

Recipient design.
An important concept in the analysis of spontaneous talk  is ‘recipient design’ (XX JOHN PLEASE FIND REFS). Recipient design means that speech is produced with sensitivity to the needs of the listener: it is designed so as to be maxinally co-operative with the listener (XX REF GRICE’s MAXIMS?). In terms of discourse, this means that the information structure of any given talk is made available to the listener, through syntax, the choice of lexis, and, importantly, prosody.

Concept-to-speech synthesis
Concept-to-speech synthesis uses text which is marked up for discourse information, rather than relying on plain text with punctuation. The SOLE project (XX REFS) is one example of this. OTHERS? 

One problem of marking up texts is that there is a danger that the mark-up is unconstrained. But our proposal suggests a small number of labels such as <LIST>, <LIST ITEM>, <APPOSITION>, <PRE> for speech leading up to one of the embedded discourse structures and <POST> for speech coming out of the emdedded structure.

Phonetic gestalts
We have identified two discourse structures which are common in the target texts: lists and appositions. They have in common the fact that they are offset from surrounding material through the use of prosodic resources. They both form phonetic ‘gestalts’. This means that they stand out as a whole because all the appropriate phonetic parameters are controlled in such as way as to produce internal coherence within the unit, and enough disjunction with surrounding speech to mark the apposition or list out as different. They have the overall structure
PRE—{list, apposition}—POST

Approaches to studying these gestalts
There are two kinds of research question which such discourse structures raise, and which are generalisable to discourse structures more generally:
1.	How are the structures set off from (or: how do they emerge from) surrounding material? (“Internal” properties, Cruttenden 1986.)
2.	What phonetic parameters are brought to bear in order to maintain the internal coherence of these structures? And what is the interrelation of these phonetic parameters? (“External” properties, Cruttenden 1986.)

The phonetics of Intonational Phrases
Information structure can be seen as being made audible by the phonetic ‘chunking’ of material into Intonational Phrases. Both lists and appositions are examples of intonational phrases which are embedded within other intonational phrases. There are a number of phonetic parameters described in the literature for both internal and external properties of IPs:

1.	Internal properties (Cruttenden 1986)
1.	Pitch characteristics:  coherent intonation contour (Chafe 1987); declination (Ladd 1986)
2.	External properties (Cruttenden 1986)
1.	Tonal characteristics (Stenström 1990, Bruce et al 1991): phrase-initial reset (Schuetze-Coburn et al. 1991), pitch movement in the nucleus and in the unstressed syllables following it (Cruttenden 1986)
2.	Temporal characteristics: pausing, phrase-final lengthening and acceleration of tempo on initial unstressed syllables (eg. Cruttenden 1986). 
3.	Pausing. What counts as a ‘pause’ is problematic (Kowal et al 1983; cf. Dankovicová 1992).
4.	Phrase-final lengthening is actually concentrated on the rhyme of the phrase-final sylable, with final-syllable codas showing proportionally more lengthening than final-syllable nuclei (eg. Turk 1999).
5.	Acceleration of tempo of phrase-initial unstressed syllables (Cruttenden 1986): is this just part of the general pattern of deceleration through the IP? (Dankovicová 1997, 1999).
6.	Change in amplitude (Streeter 1978)
7.	Change in voice quality (Chafe et al 1991; Knowles 1991).
8.	Rhythm (Lehiste 1977, Scott 1982)—increase in the duration of a foot relative to surrounding feet—can be used to signal a boundary.
9.	Segmental effects such as the blocking of assimilation across boundaries (eg Scott & Cutler 1984).

These cues do not all have to be present, and it has been argued that pitch reset is the primary cue to an intonational boundary. However, there is little experimental evidence to demonstrate this position. Streeter (1978) argues that pitch and timing are inseparable, ie. they form an integrated percept (a gestalt). Beach (1991) provides evidence for this.

The phonetics of repetition. (given and new)
This is a total mess. Sarah, perhaps you want to say something more coherent?
Fowler & Housum (1987), Hawkins and Warren (1994), Bard & Aylett (1999) XX OTHERS? showed that subsequent tokens of repeated words—broadly, ‘given’, information—tend to be shorter and less intelligible than their priors; in other words, they tend towards hypo-articulation. Hawkins & Warren argue that this may be largely due to deaccenting. Bard & Aylett argue that de-accenting is not common on second-mentions in spontaneous talk. Lists and appositions provide a useful testbed for the interaction of phonetic details in a natural discourse structure: appositions have the same referents as their heads, but use different words; while lists frequently contain repeated segmental material but different words.

Constrainedness of identified structures as a motivation for working with them.
Lists and appositions provide a highly constrained but naturally-occurring site in which to study the phonetics of intonation phrases (IPs). They are constrained on several levels:
•	Syntactically (list items are syntactically alike; appositions and head are the same syntactic category)
•	Semantically (list items share semantic or pragmatic properties; appositives and their heads have the same referent).
•	Phonetically (their prosodic characteristics both mark them out from surrounding speech and make them internally coherent).
Lists and appositions provide a natural site to test hypotheses about the nature of prosodic units and the boundaries of those units.
1.7 Appositions.

Appositions are one kind of paranethetical. The syntax-prosody interface has a complex history (eg. Selkirk 1996), but in the case of appositions, the boundarires of prosodic structures (intonational phrase) match those of the syntactic structures (noun phrase) (see Taglicht 1998).

Two or more noun phrases are in apposition when they have identity of reference (Greenbaum & Quirk 1990: 382). The apposition may not be marked in any other way than prosodically:

The biggest oil company in Africa, Shell, agreed a profit-sharing scheme with local communitites in Nigeria.
Reuters, the news and information group, is aiming toward flotation…

It is also possible for the apposition to be marked explicitly:

Linguistics, or the study of language, attracts some interesting students.
The outcome, that is Gore’s election, was a complete surprise.

Apposition has the function of providing more information about a prior word/phrase. Appositives are of the same syntactic category as the thing they are in apposition to.

Restrictive and non-restrictive apposition. (Relates to given/new?)
Apposition is non-restrictive when it contains information that is not essential in uniquely identifying the antedecent (Quirk & Greenbaum 1990: 364). All examples above are non-restrictive.

Intonational repetition in apposition.
Clauses and phrases in non-restrictive apposition tend to have the same nuclear tone as their antecedent noun or phrase (Couper-Kuhlen 1986: 150; Wichmann XX REF PLEASE JILL):

People like \/ David Steel, who was one of the \/ promoters…
The chair of  ^ Oxfam, Sir  ^ Geoffrey Wilson…

Couper-Kuhlen (1986) calls this kind of repetition a ‘co-occurrence pattern’, and a similar pattern is also found in lists. It may function as one kind of prosodic pattern which explicitly links the appositive and its head prosodically.

More reading to do, eg. Arnold et al (2000). Waiting for some more refs. from syntactician colleagues.

1.8 Lists.

Repetition of material.
Lists involve repetition of material on several levels. They involve syntactic repetition: each list item within a list is of the same syntactic category. They often (but not necessarily) involve semantic repetition (eg. a listing of a class of items, such as types of car/food/feeling, etc.). Or the repetition can have a more pragmatic effect, and rely more on the listeners’ knowledge (eg. names of people known to both speaker and hearer, books the speaker has read, activities the speaker likes, etc.). 

Lists involve phonological repetition too: for example consonant-vowel sequences are frequently repeated within lists, producing a kind of alliteration. There is of course also intonational repetition, with each item in the list (except the last) being intonationally similar to other items. 

Rhythm/isochrony.
Lists are frequently a location for isochrony (Lehiste 1975; Auer et al. 1999), so that each list item is produced ‘on beat’ with the last. This produces the expectation that there may be more to come, and could be a strategy for making it clear that a list is an invitation for the other speaker to join in in its creation.

Preference for three-partedness.
There is a marked preference for lists to be three parted: that is, they mostly consist of A, B and C. This is not to say that they must be, only that they frequently are (Jefferson 1990).

List types: complete and incomplete.
There are probably several distinct types of list. For example: a list that is ‘complete’ (in the sense that it is not extendable or intended to be extended by the speaker) may be different from an ‘incomplete’ list (in the sense that it is extendable). ‘Complete’ lists can have downsteps on the intonation of each item, while ‘incomplete’ lists perhaps cannot (XX PIERREHUMBERT & BECKMAN REF? The one with blueberries, raspberries and strawberries) Couper-Kuhlen 1986: 150; Crystal 1969: 237ff.; Schubiger 1958).

List types: completed with general list completers.
Another kind of list is the three-parted list where the final item is some sort of general completer, as in “stuff/things like that” “or whatever” “and that kind of thing”. We’re unlikely to have most of these completers in our texts, but some work our undergraduates did on these last year suggests that you can do what Sarah might call ‘hypo’ speech for them. Perhaps we’d find things like “and similar things” instead of “and stuff like that”?

Pauses.
The literature suggests that longer pauses reflect higher-level syntactic and/or prosodic boundaries (XX REFS NEEDED). Rhythmically organised lists often sound highly isochronous: this suggests that the duration of a pause may be timed so as maintain the rhythm rather than to mark phrasal complexity. Rhythmically organised lists also provide a good site to see how pauses and phrase-final lengthening interact.

‘List intonation’
‘List Intonation’ is described (but not in great detail) in a number of works. 
Halliday (1967: 17): 
/A /B /C \D.
Schubiger (1953; discussed in Crystal 1969: 237f.) 
/A /B /C \D
\A \B \C \D (“more colloquial”)
/A /B /C /D (“susceptible of continuation”)
\A \B \C /D \E (“lays emphasis on the penult”)
Tench (1996: 36):
This is basically the same analysis as Halliday and Crystal; but it emphasises “tonality”: division of the list into its intonational units. These are represented by |: 
We need milk | some bread | and butter.
We want red | white | and blue flags please.
vs. We want red white and blue flags please.

Conjunction
In English many lists are made with conjunctions (eg. X and Y and Z; X or Y or Z). The rhythm of these things seems to be X | and Y | and Z, not X and | Y and | Z. But it seems (impressionistically) that the conjunctions may have properties of both the adjacent list items, by having eg. the resonance properties of the IP to the left, but the intonation properties of things to the right.

Examples.
Below are some examples of lists in spontaneous speech, taken from a radio programme in December 1999. 
(1) Notice alliteration of /k/ and the three-partedness of this list.
BC		No I don’t think it’s vague, I think it’s very interesting that- that people’s- I mean whatever one thinks about the specific remarks, what seems to be: (.) the tone that all of these callers share, is a sense that human beings’ relationship to the earth is 
/k/		changing and has to change and that a cult
/k/	1=>	of coercion 
/k/	2=>	conquest
	3=>	and dominion 
		is what is being challenged.
(2) Again, alliteration and three-partedness.
Bishop		things that were being said 
/p/	1=>	by Penny
	2=>	and Tony
/p/	3=>	and Pamela
		all relate to (.) this millennium resolution
(3) …and again (all within about 10 minutes of spontaneous talk).
BC		it was what we did with it ((technology)) and that’s 
/st/x2		really the story of all this stuff 
		none of this stuff in the end whether we’re talking about
/p/	1=>	inventors of pills 
/p/	2=>	inventors of penicillin
	3=>	inventors of chips 
		they themselves are heroic.

2. OUTLINE OF PROPOSED RESEARCH.

This section is still speculative, and we have to make some decisions. We have had a brainstorming session at York and tried to pull together as many ideas as we can, without at this stage evaluating them. We think it might be useful for you to do the same.

I’ve arranged them so that the general topics are most prominent, and tried to highlight where I can how lists and appositions relate to each topic. I hope this will make it easier later to pull together the workpackages either according to data type or according to topic.

From our brainstorming: Some potentially interesting research questions.
Set out here according to three main areas of phonetic research.

2.1 Tempo and rhythm
2.1.1 Internal factors.

•	Isochrony: the percept of ‘beats’ coming at equally spaced intervals. LISTS.
•	Tempo in relation to IP length. Are longer list items produced at a faster tempo than shorter ones, to maintain rhythmicity? LIST.
•	What are the phonetic correlates of ‘acceleration’ and ‘deceleration’?
•	Duration of pause at IP boundaries. In LIST it may vary as a function of the isochronous beats.

2.1.2 External factors.

•	What are the phonetic correlates of ‘acceleration’ and ‘deceleration’? (eg. at the boundary of a PRE to an APPOSITION or LIST; or at the boundary of one LIST ITEM and another; or at the boundary of the LIST or APPOSITION and the POST). LIST and APPOSITION.
•	Relation of embedded IP to surrounding IPs. LIST and APPOSITION.
•	Duration of pause at IP boundaries. Relation of pause duration to tempo and rhythm.
•	Relation of pause to segmental lengthening. Phrase-final lengthening affects mostly codas (Turk 1999). What relation is there between lengthening of a segment and the duration of a pause? LIST and APPOSITION.
•	Tempo of PRE and of POST: how alike do they have to be to produce the coherent impression of an embedded intervening IP? Are lists and appositions alike in this? LIST and APPOSITION.

2.2 Intonation
2.2.1 Internal factors.
•	Alignment of pitch accents within syllables. LIST and APPOSITION.
•	Reduplication of pitch accents between items. How alike/how variable can two pitch contours be in order to be heard as ‘the same’ and therefore produce the percept of a list? (Does this provide one possible new testing bed for intonation?) LIST.
•	Pitch range as a function of information structure. APPOSITION.

2.2.2 External factors.
•	Reduplication of pitch accents between head NP and appositive. APPOSITION.
•	Pitch range of embedded IP in relation to PRE and POST. LIST and APPOSITION.
•	Pitch reset across IP boundaries. Relation to pause?  LIST and APPOSITION.
•	Relation of pitch at end of PRE and start of POST: how do the two relate? does pitch pick up where it left off? LIST and APPOSITION.

2.3 Articulation
2.3.1 Internal factors.
•	Hyper-/hypo speech in relation to IP structures: eg. repetition of material; relation to tempo; relation to type of speech sound (eg. when vowels are centralised, are plosives also more likely to have more open articulations? Relation to duration?). LIST and APPOSITION.
•	What are the phonetic relations between hypo- and hyper-speech sounds? Is eg. a fricative which derives from a plosive in hypo-speech the same as a fricative that is ‘underlyingly’ a fricative? LIST and APPOSITION.
•	What is the relation of the source/airflow in unstressed syllables to the articulation of consonants in those syllables? LIST and APPOSITION.
•	What is the relation of resonance/coarticulation across boundaries between list items with other demarcative things like intonation? LIST.

2.3.2 External factors.
•	Coarticulation and resonance spread across boundaries. LIST and APPOSITION.

2.4 Integration
•	What is the relation of amplitude to all the other parameters? Do we need to model it?
•	If we work on the same material, can we produce the information that allows us to explain why these two structures produce a phonetic gestalt?
•	Is one way to integrate to do experiments with trading relations between two sites?

2.5 Methodology
It seems to us that we have to identify techniques for analysis. Possible ideas:
•	Identifying rhythmic beats using Fred Cummins’ & Robert Port’s model. (York have the unix code.)
•	Manipulation of HLsyn/PROCSY
•	Analysis of materials in various permutations (described in more detail in ProSynth 2.4, not repeated here)

2.6 Computing Infrastructure
The computational infrastructure for the project will build on the tools developed in the first two ProSynth projects.  The ProSynth synthesis system is an open architecture for synthesis which uses a chain of simple programs and scripts to flesh out a linguistic description of an utterance expressed in XML.  Input to the system is marked-up text, and output is compatible with a range of signal generation components, including MBROLA, Festival, BT Laureate, and HLSYN, as well as prosody manipulated natural speech.  The aim has been to treat synthesis as interpretation, where the context in which a component occurs (established either by its position in the linguistic structure or explicitly by markup) controls the form that it is realised.  A simple scripting language called ProXML was developed to express knowledge about interpretation in a declarative formalism which is easier to enhance and maintain than a set of interacting rules.  This software is publicly available.

The previous projects used other statistical tools for data analysis, including CART, GLM and functional approximation tools.  The results of these analyses were however always expressed in the ProXML formalism.
2.6.1 Development of Tools

A weakness of the current tools is their lack of support for corpus-based synthesis tools using a unit selection algorithm based on prosodic and phonetic features.  To evaluate the phonetic representations we develop on this project, we shall implement a unit-selection based synthesis system for English.  This will use the open-source unit-selection system under development by Stöbler et al at the University of Bonn, in combination with our existing ProSynth databases of read speech. This system  will allow us to store and retrieve signal sections according to a range of possible parameters, both prosodic and phonetic, and to concatenate and smooth the result. This tool can then be used to investigate the effectiveness of our phonetic interpretations for unit selection.
 
2.6.2 Linguistic Markup

The project will involve much more text-level markup than the previous projects.  This means that mechanisms will need to be developed to pass information expressed as operators on words or word strings down into the prosodic hierarchy. We would like to do this in a principled way, rather than by confusing levels by using phonological markup on the word strings. Thus we would avoid markup schemes which added pitch accent types to words, or indicated prosodic phrasing at the word level. Text markup should instead be related to properties of words or consituents with regard to information structure.

BIBLIOGRAPHY
Not all of these are used in the text above, but I think they’re useful. If someone else can see how to put them in, do.

Arnold, Jennifer, Thomas Wasow, Anthony Losongco, & Ryan Ginstrom (2000). Heaviness vs. Newness: The effects  of complexity and information structure on constituent ordering, Language 76, 28-55.  NOT HAD TIME TO READ YET.
Auer, Peter, Elizabeth Couper-Kuhlen & Frank Müller (1999). Language in time: the rhythm and tempo of spoken interaction. Oxford, OUP.
Bard, E G & M P Aylett (1999). The dissociation of deaccenting, givenness and syntactic role in spontaneous speech. Proceedings of ICPhS XIV, San Francisco, 1999. 1753-1756.
Beach, C. M. (1991) The interpretation of prosodic patterns at points of syntactic structure ambiguity: Evidence of cue trading relations. Journal of Memory and Language, 30, 644-663.
Bolinger, Dwight Le Merton (1989). Intonation and its uses: melody in grammar and discourse. Stanford, U.P.
Bruce, G., Granström, B. & House, D. (1991) Strategies for prosodic phrasing in Swedish. In Proceedings of 12th International Congress of Phonetic Sciences, vol. 4, pp. 182-185. Aix-en-Provence.
Chafe, W. (1987) Cognitive constraints on information flow. In Coherence and Grounding in Discourse, (R. S. Tomlin, editor), pp. 21-51. Amsterdam: Benjamin.
Couper-Kuhlen Elizabeth (1986) An introduction to English prosody. London, etc., Arnold, 1986.
Cruttenden, Alan (1997). Intonation. Cambridge, etc., U.P., 1986; 1997.
Crystal, David (1969). Prosodic systems and intonation in English. Cambridge: CUP.
Dankovičová, J. (1992) The minimum pause duration in spontaneous speech, PROPH - Progress Reports from Oxford Phonetics, 5, 17-24.
Dankovičová, J. (1997) The domain of articulation rate variation in Czech, Journal of Phonetics, 25, 287-312.
Dankovičová, J. (1998) The linguistic basis of articulation rate variation in Czech. Unpublished D.Phil. thesis, University of Oxford. 
Dankovičová, J. (1999)  Articulation rate variation within the intonation phrase in Czech and English. In Proceedings of  the XIVth International Congress of Phonetic Sciences, San Francisco, 269-272.
Fowler, C & J Housum (1987). Talkers’ signalling of ‘new’ and ‘old’ words in speech and listeners’ perception and use of the distinction. Journal of Memory & Language 37, 24-40.
Goldman-Eisler, F. (1972) Pauses, clauses, sentences, Language and Speech, 15, 103-113.
Gussenhoven, C. & Rietveld, A. C. M. (1992) Intonation contours, prosodic structure and preboundary lengthening, Journal of Phonetics, 20, 283-303.
Halliday, Michael Alexander Kirkwood (1967). Intonation and grammar in British English. The Hague, etc., Mouton. Janua linguarum. Series practica, 48.
Hawkins, S & P Warren (1994). Phonetic influences on the intelligibility of conversational speech. Journal of Phonetics 22, 493-511.
Jefferson, Gail (1990). List-construction as a task and resource. In George Psathas (ed.) Studies in ethnomethodology and conversation analysis 1, Interaction competence, 63-92.
Knowles, G. (1991) Prosodic labelling: the problem of tone group boundaries, In English computer corpora: selected papers and research guide (S. Johansson & A-B. Stenström, editors). Berlin: Mouton de Gruyter.
Kowal, S., Wiese, R. & O’Connell, D. C. (1983) The use of time in storytelling, Language and Speech, 26, 377-392.
Ladd, D. R. (1986) Intonational phrasing: The case for recursive prosodic structure, Phonology Yearbook, 3, 311-340.
Ladd, D. Robert (1996). Intonational Phonology. Cambridge: CUP.
Lehiste, I. (1977) Isochrony reconsidered. Journal of Phonetics, 5, 253-263.
Lerner, G. (1994). Responsive list construction: A conversational resource for accomplishing multifaceted social action. Journal of Language and Social Psychology 13, 20-33.
Monaghan, Alex (1999). State-of-the-art summary of European synthetic prosody R&D. COST 258 — The naturalness of synthetic speech. 
http://www.unil.ch/imm/docs/LAIP/COST_258/Scientific/SOAPs/soap__monaghan.htm
Nooteboom, Sieb (1997). The Prosody of Speech: melody and rhythm. In Hardcastle & Laver (eds.) The Handbook of Phonetic Sciences.
Pierrehumbert, Janet Breckenridge (1987). The phonology and phonetics of English intonation. Bloomington, Indiana Univ. Linguistics Club.
PIERREHUMBERT XX MORE REFS NEEDED?
Schuetze-Coburn, S., Shapley, M. & Weber, E. G. (1991) Units of intonation in discourse: A comparison of acoustic and auditory analyses, Language and Speech, 34, 207-234.
Scott, D. R. (1982) Duration as a cue to the perception of a phrase boundary. JASA¸ 71, 996-1007.
Scott, D. R.& Cutler, A. (1984) Segmental phonology and the perception of syntactic structure. Journal of Verbal Learning and Verbal Behaviour, 23, 450-466.
Selkirk, Elizabeth (1996). Sentence prosody: intonation, stress and phrasing. In J Goldsmith (ed.) The Handbook of phonological theory. Oxfrod, Blackwell. 550-569.
Stenström (1990) Pauses in monologue and dialogue. In The London-Lund corpus of spoken English: Description and research (J. Svartvik, editor), Lund Univesity Press, Lund.
Streeter, L. (1978) Acoustic determinants of phrase boundary perception. JASA, 64, 1582-1592.
Taglicht, Josef (1998). Constraints on intonational phrasing in English. Journal of Linguistics 34, 181-211.
Taylor, Paul Alexander A phonetic model of intonation in English.  Bloomington, Indiana Univ. Linguistics Club, 1994. RAO HASN’T READ THIS. 
Turk, A. E. (1999) Structural influences on boundary related lengthening in English. In Proceedings of  the XIVth International Congress of Phonetic Sciences, San Francisco, pp. 237-240.
Tench, Paul (1996). The intonation systems of English.  London, Cassell, 1996.