Section 7.4. in Software Add qr barcode in Software Section 7.4.

Section 7.4. generate, create qr codes none on software projects QR Code Module Size and Area Phonology: the linguistic organisation of speech avoiding the segment exp losion problem of SPE. The theories of Articulatory Phonology [70] and Feature Geometry [100], [306], [386] are based on this idea. In addition to the issues discussed in this chapter, it should be understood that the eld of phonology tackles many issues which aren t directly relevant to speech synthesis needs, such as say nding the set of language universals.

Optimality Theory is one such model which has gained particular attention in recent years [362]. In addition to this, the emphasis on phonology even within directly relevant topics is often somewhat different from what we require from an engineering perspective. In particular the old issue of economy comes up again and again, with phonologists striving for every more natural and economical representations, without usually much interest in assessing the processing requirements incurred.

The general trends in phonology are clear though; a move away from nite state, linear models towards more complex feature organisations, a move from ordered context-sensitive rules to systems which use constraints and dependencies, and a move from procedural systems to declarative systems. Somewhat ironically, while most phonologists trace their work back to SPE, the formal side of this approach has largely been forgotten, and few works in phonology since have anywhere near the level of explicitness and comprehensiveness of that work. A notable exception comes from the work of Computational Phonology [43].

. 7.4.4 Syllables One of the most important aspects of phonology concerns the structural representation of sound patterns above the phoneme. We have already seen that morpheme boundaries are signi cant (e.g.

in the difference between the realisation of PENS and PENCE) as are word boundaries. In addition to these, we nd it is very useful to make use of a third unit, the syllable as this also helps explain many of the effects and patterns in speech. As we have already seen, the syllable provides a solid basis for de ning the phonotactic grammars of what constitutes a legal word.

If we de ne a grammar for a syllable, it is an easy matter to de ne a grammar for any words by simply including more syllables and any possibly special sequences for word beginnings and ends. That said, it is interesting to ask real evidence do we have for syllables as real entities. We seem to instinctively know that SET, FROM and BATH have one syllable; that TABLE, WATER and MACHINE have two, and OPERATE, COMPUTER and ORGANISE have three.

These judgments seem intuitive and are not dependent on any expert knowledge. Secondly, if we consider singing we see that in normal singing each note is sung with one syllable. If this principle is broken the singing can sound awkward if syllables are inappropriately squeezed in or elongated over several notes.

Thirdly, syllables seem to act as the basic unit of many aspects of prosody. Syllables carry stress such that in THE PROJECT the rst syllable of PROJECT is stressed, but in PROJECT THAT LIGHT the second gets the stress. There are no other possibilities - it is not possible to stress the /p r/ and not the vowel, or any other individual phone.

So what exactly is a syllable We will take the view that the syllable is a unit of organisation. As such, all words are composed of a whole number of syllables, and all syllables are composed. Phonetics and Phonology of a whole nu mber of phonemes. For an initial working de nition, we will state that a syllable is a vowel surrounded by consonants. This de nition seems to ts the facts fairly well - in all the above cases the numbers of vowels and numbers of syllables were the same, and again from singing we can see that the vowel seems to be the centre of the note.

There is one commonly raised exception to this, namely the existence of so called syllabic consonants. Some phoneticians give two syllable words such as BOTTLE and BUTTON the transcriptions /b aa t l/ and /b ah t n/, in which the second syllable is comprised only of /l/ and /n/ sounds. Conventions differ as whether to allow this, or use the alternative, which gives these words the transcriptions /b aa t ax l/ and /b ah t ax n/.

There is probably no real way to decide from a phonetic point of view, but practical TTS experience has shown no de ciencies in using /ax/ and as this makes the de nition of the syllable simpler, we shall use that and not use syllabic consonants. So, taking the vowel as the centre of the syllable, all we have to do is decide which consonants belong to which syllables. In words such as HOTEL, we can safely say that the /h/ belongs to the rst syllable and the /l/ to the last, but what about the /t/ There are a number of positions to take on this.

One position is the so-called maximal onset principle where consonants that potentially could be in the onset or coda of a syllable are taken as being in the onset. Using the symbol /./ to denote a syllable boundary, HOTEL is then represented as /h ow .

t eh l/. This will provide a satisfactory account for many words, and it can be argued that this has some cognitive reality because, again from singing, we nd that consonants tend to follow this pattern. There are a number of problems however.

Firstly, in non-word-initial syllables which have /s t r/ and other such sequences, {INSTRUCT, /ih n s t r ah k t/} it can be argued that the /s/ attaches to the rst syllable and not the second. Secondly, consider such words as { BOOKEND, /b uh k eh n d/} - here it de nitely seems that the /k/ attaches to the rst syllable - in fact a syllable nal /k/ and an syllable initial one sound quite different and so /b uh k . eh n d/ sounds different from /b uh .

k eh n d/. There is an obvious reason to this, namely that BOOKEND is a word formed by compounding BOOK and END, and it seems that the word/morpheme boundary has been preserved as a syllable boundary. One of the main reasons we are interested in syllables is that pattern of syllables within a word, and the pattern of phonemes within a syllable helps determine much of the phonemic variation due to allophones and coarticulation.

Hence it is often useful to assign a basic constituent structure to describe the structure of phonemes internal to a syllable. We will explain one way of doing this, in which four basic constituents are used, called the onset, rhyme, nucleus and coda. The syllable structure for the single syllable word STRENGTH in these terms is:.

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