Does "send" require a "to"?

Question

Is the following grammatical?

Should I send the letter to her?

If it is, then how come that send can also be used without to?

Should I send her the letter?

What about the use of send in a sentence like "It sent her mad"?

Answer 1

In some languages, the noun denoting the 'recipient' of something is frequently in the dative case.

In English, the 'recipient' can be shown in two ways:

As an indirect object, usually preceding the direct object: He sent/gave me the letter;

Following the preposition 'to' following the direct object: He sent/gave the letter to me.

Some pronoun/pronoun and pronoun nouns are less commonly used than others.

Acceptable/Common:

I gave John the letter. I gave the letter to John.

I gave him the letter. I gave the letter to him.

I gave it to John.

I gave it to him.

Doubtful/Less Common:

I gave John it.

I gave him it.