Intonational tune

The intonation tune can be broadly described as the core pitch pattern of an utterance. Tunes differ from one another in type and in association. By using different types of tunes, the speaker ean express for example an emotion sueh as surprise, disbelief or excitement. The association of the tune conneets the prosodie part of intonation (the tune itself) to the verbal part, by associating parts of the tune with particular words. By shifting association from John to match in examples 118 and 119, one can convey different effeets. By varying the t) e of tune, one can also express different effects as in example 120. 

Describing tune type is perhaps the most difficult issue in prosody. Tune schemes can be broadly divided into those which classify tunes using dynamie features (rises and falls) and those which use static features (tones). Theories also vary in the size of the units they use. Global descriptions make use of a few basic patterns that cover the entire phrase, atomistic theories make use of smaller units that combine together to form larger patterns. Jones [242] is at the global end of the seale, the British school [333], [193] uses sub-phrase units (see Section 9.3.1, while the AM school [352], [351] and the Dutch school [446] use units whieh are smaller still (Seetions 9.3.2, 9.3.3. 

Much of the discussion on the subject of tune centres around how to deseribe pitch accents. A pitch accent is commonly manifested in the FO contour as a (relatively) sudden excursion from the previous contour values. This is where association comes in, as pitch accents only occur in conjunction with prominent syllables, and in doing so attract attention to that syllable. Pitch accents can only occur in association with prominent syllables (see Section 6.3 on prominence), but need not occur on all prominent syllables. 

Most work agrees that the prosodic phrase as described in Section 6.2 is the basic domain of intonational tune patterns. Hence the phrase not only groups words together, it also serves as the start and end of each section of tune. In many models, we have a nuclear accent, which occurs once per phrase. 

The other main area of interest in tune description concerns what happens at the ends of intonation phrases. Often FO is low at a phrase boundary, but in many circumstances FO is high. For instance, if another phrase directly follows the current one, a continuation rise may be present. If the tune is that of a yes/no question, the final pitch may also be high. The British school deals with these effects by using different nuclear accent and tail configurations. The AM model makes use of high and low boundary tones which distinguish the different types of contour. 

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Here we have explicitly separated prominence from the tune part of intonation, and so for our purposes intonation prediction is specifically the prediction of intonational tune from text, rather than the broader definition of this problem that encompass predicting tune, accentuation and sometimes phrasing. 

Of all the prosodic phenomena we have examined intonational tune is the most heavily related to augmentative and particularly affective content. In situations where these effects are absent, we can say to a first approximation that all utterances have in fact the same intonational tune the only differences occur as to where the pitch accents and boundary tones which make up this tune are positioned. Hence we can almost argue that for discourse neutral synthesis, there simply isn t any intonational tune prediction to be done. In other words, the real task is to predict a suitable FO contour that e q)resses the prominence and phrasing patterns and encodes the suprasegmental, rather than true prosodic patterns of the utteranee. 

It would be impossible to show all the possible types of intonational tune for English, but six common tunes which vary because of their nuclear accent types are shown in Figures 9.1 to 9.6. These examples are not comprehensive and other theories may classify these contours differently. 

The same effect is observable in intonation by increasing the overall pitch of an utterance while keeping the basic tune pattern constant, the perceived tune remains the same. The relationship between intonational tunes in different pitch ranges is not as simple as the musical equivalent. It has been shown that the increase or decrease in pitch range need not be constant throughout the phrase, as utterances always tend towards a fairly constant final FO value. 

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