syllable) is pronounced with greater force than the syllable ad, although when the word is not pronounced with this final intonation there may be no difference between the levels of stress of these two syllables. Prosodic stress can shift for various pragmatic functions, such as focus or contrast. For instance, in the dialogue Is it brunch tomorrow? No, it's dinner tomorrow, the extra stress shifts from the last stressed syllable of the sentence, tomorrow, to the last stressed syllable of the emphasized word, dinner. Grammatical function words are usually prosodically unstressed, although they can acquire stress when emphasized (as in Did you find the cat? Well, I found a cat). Many English function words have distinct strong and weak pronunciations; for example, the word a in the last example is pronounced , while the more common unstressed a is pronounced . See Weak and strong forms in English. Rhythm English is claimed to be a stress-timed language. That is, stressed syllables tend to appear with a more or less regular rhythm, while non-stressed syllables are shortened to accommodate this. For example, in the sentence One make of car is better than another, the syllables one, make, car, bett- and will be stressed and relatively long, while the other syllables will be considerably shorter. The theory of stress-timing predicts that each of the three unstressed syllables in between bett- and will be shorter than the syllable of between make and car, because three syllables must fit into the same amount of time as that available for of. However, it should not be assumed that all varieties of English are stress-timed in this way. The English spoken in the West Indies, in Africa and in India are probably better characterized as syllable-timed, though the lack of an agreed scientific test for categorizing an accent or language as stress-timed or syllable-timed may lead one to doubt the value of such a characterization. Intonation Phonological contrasts in intonation can be said to be found in three different and independent domains. In the work of Halliday the following names are proposed: Tonality for the distribution of continuous speech into tone groups. Tonicity for the placing of the principal accent on a particular syllable of a word, making it the tonic syllable. This is the domain also referred to as prosodic stress or sentence stress. Tone for the choice of pitch movement on the tonic syllable.