Suppletion
The last type of inflection presented here is suppletion. Suppletion is said to take place when the syntax requires a form of a lexeme that is not morphologically predictable. In English, the paradigm for the verb be is characterized by suppletion. Am, are, is, was, were, and be have completely different phonological shapes, and they are not predictable on the basis of the paradigms of other English verbs. We also find suppletion with pronouns. Compare I and me or she and her. Suppletion is most likely to be found in the paradigms of high-frequency words, as seen in the following box.
We can look to historical linguistics for an explanation for how suppletive forms arise. The paradigm of the verb ‘to go’ in French, for example, comes from three different Latin sources. The infinitive, aller, and the first person and second person plural forms in the present, allons ‘we go’ and allez ‘you (pl) go’, come from Latin ambulāre ‘to walk, to walk along’. The stem of future and conditional forms, such as irai ‘will go (1sg)’, has evolved from the Latin verb īre ‘to go’. Finally, forms like vais ‘go (1sg)’ or vont ‘go (3pl)’ come from Latin vādere ‘to go, to walk’. The idiosyncrasies of languages today can often be explained by looking at the languages of yesterday.
In certain cases, such as with catch∼caught or think∼thought and other verbs like them in English, it is most convenient to speak of partial suppletion. In these cases, the initial phoneme or phonemes of the word remain the same, but there is both internal change and change to the end of the word (loss of segments and addition of a past tense indicator [t]).
