We all know there are certain irregular verbs which do not quite fit into the normal paradigm for forming the past tense and the past participle. In other words, they do not form the past tense by adding -ed and the past participle by adding -ed/-en. These include verbs like ‘come’: come came come; ‘buy’: buy bought bought; and ’sing’: sing sang sung. Those of us who are not native speakers probably had a hard time trying to remember all these forms.
But being merely irregular is fine, at least they look alike. There are a few words in English which may seem truly out of place. Foremost of these is the verb ‘be’: am/is/are was/were been. Its tensed forms are simply too creative if they were really created out of the base form. Inquisitive as we are, we want to ask why and how.
If we trace back to the origin of this word, we find that the various forms of ’be’ actually come from 3 different verbs.
be: from Old English beon, meaning “come into being, become”
am/is/are: from Old English eom, meaning “remain, exist”
was/were: from Old English wesan, meaning “remain, stay”
At first, the verb eom could only be used in the present tense. When one needed to talk about the past, another verb, namely wesan, had to be used. These two verbs were then gradually re-analyzed as different forms of the same verb meaning “to be, to exist”.
The form beon carried a meaning of coming into existence, so it was more about a change of states, whereas the other two verbs described the state of being existent (cf. become vs. be). It was re-analyzed and used as the future form of eom until in late Middle English, its use was taken over by eom and remained only as the infinitive form.
[Interestingly, this also happens in other languages, such as Italian. In Italian, whereas the verb essere “to be” is used in the present tense, when one wants to talk about the past with the present perfect, the verb stare “to stay” has to be used instead.]
This process, that words of different origins are used as different forms of the same word, is called suppletion.
Another example of suppletion is the verb ‘go’: go went gone, with ’went’ coming from the verb wend, similarly meaning “to go”.
Suppletion also exists in nouns and adjectives. The forms ‘person/people’ come from Latin persona “human being” and populus “people” (cf. population) respectively. ‘Better/best’, the comparative and superlative forms of ‘good’, come from a separate Old English word bōt, originally meaning ”remedy”. ‘Worse/worst’ come from Old English wyrresta, meaning “to confuse”. The adverb ‘well’ is historically related to the word ‘will’, rather than with its present adjective counterpart ‘good’.