8.3.3 Tune

Two utterances with the same prominence and phrasing patterns can still differ prosodically by having different tunes. The tune of an utterance is the rise and fall of its F0 over time. A very obvious example of tune is the difference between statements and yes-no questions in English. The same sentence can be said with a final rise in F0 to indicate a yes-no-question, or a final fall in F0 to indicate a declarative intonation. Fig. 8.8 shows the F0 track of the same words spoken as a question or a statement. Note that the question rises at the end; this is often called a question rise. The falling intonation of the statement is called a final fall.

Figure 8.8 The same text read as the statement You know what I mean. (on the left) and as a question You know what I mean? (on the right). Notice that yes-no-question intonation in English has a sharp final rise in F0.

It turns out that English makes very wide use of tune to express meaning. Besides this well known rise for yes-no questions, an English phrase containing a list of nouns separated by commas often has a short rise called a continuation rise after each noun. English also has characteristic contours to express contradiction, to express surprise, and many more.

The mapping between meaning and tune in English is extremely complex, and linguistic theories of intonation like ToBI have only begun to develop sophisticated models of this mapping.

In practice, therefore, most synthesis systems just distinguish two or three tunes, such as the continuation rise (at commas), the question rise (at question mark if the question is a yes-no question), and a final fall otherwise.