Special Realizations of Morphemes: Suppletion
As discussed in the preceding paragraph on allomorphs, the distribution of allomorphs of the same morpheme is either phonologically conditioned, determined by the immediate grammatical context, or it may be conditioned lexically.
Yet, in some admittedly rare cases phonological, grammatical as well as lexical factors are irrelevant vis-à-vis the selection of allomorphs – that is to say, the allomorphs of a given morpheme are phonetically unrelated. This linguistic phenomenon has caused some to comment on the craziness of the English language, as illustrated in the following poem:
Published in The Linguist No.2, 1991.
It is good and better, not gooder: allomorphs of only one morpheme that are phonetically unrelated are called suppletion. Most of the irregular plural forms in the excerpt mark the change in number internally, such as foot and feet or goose and geese. In our mental lexicon, these suppletive forms must be listed separately as they represent exceptions.