Most verbs get conjugated equally...you read, you're reading now, you will have read. But "Can" is weird, it's a verb, but "to can" doesn't make sense...instead we say "to be able to." In the present tense. Past tense "could" however, is fine!

But this is the cool part, the present participle of can doesn't exist, which would mean "I am being able" would, if conjugated normally be "I am canning." Except the present participle of Can does exist, it's spelled "cunning" we just don't use it that way anymore.

Cunning used to be a verb/gerund meaning "currently being able" or, less clumsily "having skill." But, over time, as Can lost its normal conjugation, it became "To be able...through deceit" which is wild.

And all of this comes from "cun" the same root as "to know." Also where we get "canny" (shrewd and aware) "uncouth" (unaware of norms) and "reconnaissance" (to find stuff out.)

I have been informed that "can" doesn't conjugate properly because it's a "modal" verb...it accompanies another verb to "indicate modality" (which, no, I cannot explain). Other modal verbs include Can, Should, Would, May and Will.