That gets down to what you mean by “acceptable”. Octopi is not a natural derivation of octopus as the plural is octopodes just like “aint” is not a natural derivation of any form of the verb “is” BUT in both aint and octopi’s case most understand those words so they might be acceptable depending.
TIL: I thought it was acceptable
That gets down to what you mean by “acceptable”. Octopi is not a natural derivation of octopus as the plural is octopodes just like “aint” is not a natural derivation of any form of the verb “is” BUT in both aint and octopi’s case most understand those words so they might be acceptable depending.