The smallest elements of meaning
Some of the commonest ‘words’ in English have more than one element of meaning squeezed into them. Man and men both refer to adult human males, but the first singles out ,just one while the second refers to more than one. Go and went both signify motion away from the speaker’s frame of reference, but the second shifts the time frame to the past, while the first does not. Two elements of meaning in each case. Contractions like don’t and can’t involve the lack of any past reference, and the negation by the n’t. Am, is and has involve three elements, the ‘person’, first or third, the singularity, and the lack of any past reference. These minimal elements of meaning are known as ‘morphemes’.
These cases contrast with the ‘regular’ forms like babies, uncles, aunts, witches, where the two morphemes are obvious and transparent, with a root on the left and a plural morpheme, denoting more than one, on the right, subject to a rule without an exception in the language that changes the form according to the last sound of the stem, as in pats, pans, and patches, apart from the handful of irregular forms like men, women, and children.
In verbs like be, have, go, fall, there is a contrast with regular cases like exist, possess, travel, which add a different ED morpheme, again on the right, and again without exception, to denote some reference to a time frame other than the immediately verifiable present, as in “If I had existed in the past, I would probably have died before I was this old” – with a specification of counterfactually in the had as well as its syntactic role.
In be and go and the past forms, was, were and went, the change is in the root. In the other irregular cases, of which there are several hundred, mostly very common, in fell, as opposed to fall, the vowel changes, in spent as opposed to spend, the voicing of the final consonant changes, in slept as opposed to sleep, both the vowel changes and a voiceless form of the regular D is added. The only way to generalise across all of these cases is to say that the tense is expressed by the form as a whole with two morphemes – whether these are separable, as in the regular cases, or not.