Introducing clitics

Consider the sentence Pat's a linguist. If we transcribe the sequence Pat's phonetically we can see that it forms a single syllable, /pæts/, which expresses both the subject of the sentence ‘Pat’ and the verb. A more transparent way of representing the structure would be to pronounce the sentence as Pat is a linguist. But in the sequence Pat's the verb is has been shortened to just a single consonant and has been attached to the noun Pat in the manner of a suffix. In one sense, then, /pæts/ is composed of two words, even though it's pronounced as a single word. Put differently, the 's is phonologically just the final part of /pæts/ but in terms of the sentence structure it functions as the main verb of the sentence.

This type of behaviour makes 's a typical instance of a clitic. In the present case the clitic is a form of a word which is phonologically attached to another word, its host. The 's corresponds to another form of the same word which doesn't show the same reliance on a phonological host. In Pat is a linguist we can pause between Pat and is or even insert another word: Pat, apparently, is a linguist. Similarly, if we want to confirm that Pat really is a linguist we can put the main emphasis or accent on the word is and say Pat (really) IS a linguist. None of these things is possible with the clitic form 's. The full form is therefore behaves like a genuine word, while the clitic 's behaves more like a suffix. A clitic which attaches to the right edge of its host, like a suffix, is called an enclitic. A clitic which attaches to the left edge of its host is called a proclitic. (There are also endoclitics which attach inside their host, in the manner of an infix, though these are much rarer.)