I really can't understand why this verb changes to "am", "is", etc. The common answer is "just became as historical legacy", but how actually it happend?

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    Welcome to Linguistics.SE! This is due to a process known as suppletion which causes several roots to merge, leading to this kind of 'mixed paradigms'. In the question I linked the factors playing a role in suppletion are discussed.
    – Keelan
    Jun 21, 2019 at 15:10
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    The "verb be" doesn't change to anything. That's just a way of talking about paradigms. The fact is that people say I am instead of *I is or *I be. You can say there's a special verb "am" that means "be" but is used only in the first person singular and in the present tense, while the verb be is never used in the first person singular present tense. That sounds kind of silly, so we say they're the "same verb", but they aren't, really. They're just two different forms in the same paradigm. The story of how they got into the same paradigm is another matter.
    – jlawler
    Jun 21, 2019 at 15:27
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    There are a lot of details specific to "be": is that what you are looking for?
    – user6726
    Jun 21, 2019 at 15:27
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    @user6726 true. I have retracted my close vote.
    – Keelan
    Jun 21, 2019 at 16:58

1 Answer 1


The basic intuition here is that the most common verbs are on average the most irregular. It is very hard for people to remember irregular forms of uncommon verbs, we tend to regularise them over time.

Well, to be is the most common verb of all.

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    This explains how the situation is maintained, not how it came to be.
    – Keelan
    Jun 24, 2019 at 10:35
  • Depends. Do we consider it the default natural state does of things that words used in different contexts have different roots, or that they share roots via some paradigm? Which one requires explanation? Jun 24, 2019 at 19:13

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