According to Crystal (1969:203), intonational units are 'more distinct and linguistically more replicable than others'. He illustrated the point with some figures that 'when native speakers were presented with the task of repeating an utterance, there was maximum agreement (84.8%) over the location of tone-unit boundaries, agreement over tonicity was 81.6%; onset locaiton yielded an agreement of 77.3%, and the exponent of nucleus an agreement of 74.4%.
Tone Unit Identification
Tone units are difined by Crystal (1969:204) as an audio description of grammatical contrast. A semantic approach works on the amorphous notion of the sense group. As the extra-linguistic phenomenon, it is treated as somewhat like a 'breath-group'.
Each tone unit consists of onepeak of prominence in the form of a nuclear pitch movement. the tone-unit boundary is indicated by two phonetics factors: a perceivable pitch change, rise or fall; the presence of junctural features at the end of each tone. The decriptors of the internal structure of the tone unit includes: prehead, head, nucleus, and tail.
The tonal system, i.e. nuclear tone is divided into three main types: simple, compound, and complex. The simple tone shows unidirectional pitch movement: rising, falling and level. Complex tone consists of fall-rise and rise-fall. Compound tone is known as correlative or binuclear tones. They are combinations of two kinetic elements of different major phonetic types acting as isngle unit.
