Why is it I and you are considered as plural?

Answer 1

The personal pronouns I and it are singular only. The personal pronoun you is both singular and plural.

The first person pronoun I is the subjective, the objective is me.

The third person pronoun it is the subjective and the objective.

The plural form for the subjective I is we; the plural form for the objective me is us.

The plural form for the subjective it is they; the plural form for the objective it is them.

The second person pronoun you is both singular and plural, both subjective and objective. Old English once used a different form for number and case:

• Nominative singular: Thou
• Nominative plural: Ye
• Objective singular: Thee
• Objective plural: You

But, over the centuries, the form 'you' became used for all of these functions.

Answer 2

The plural first person, subjective pronoun is we. For example:

You and I can meet at six and we can take just one car to the concert.

If I were to say "you and I are friends" I would be talking about two people, not just myself. Hypothetically let's say that your name is Fred, so you and I would mean Blobbert and Fred. Anything more than one person is plural, that's what the term means, more than one.