are these options correct?

[allthewayanime]

I would like to know if the following options are correct:

The best way to learn a language is to speak /by speaking/speaking/speak it.

[JohnParis]

The best way to learn a language is to speak the language.
The best way to learn a language is to speak it.

The best way to learn a language is by speaking the language.
The best way to learn a language is by speaking it.

The two sentences ending with "the language" are grammatical, but they are also awkward and stilted. The other two ending in "it" are - strictly speaking - not grammatical because they end with a preposition. The "rule" about ending a sentence with a preposition is fast becoming obsolete and I have no problem with the sentences above.

[allthewayanime]

In a sentence like this, would both options be correct:

All I want to do for Christmas is (to) go skiing.

[shannico]

The two sentences ending with "the language" are grammatical, but they are also awkward and stilted. The other two ending in "it" are - strictly speaking - not grammatical because they end with a preposition. The "rule" about ending a sentence with a preposition is fast becoming obsolete and I have no problem with the sentences above.

Excuse me John, did you mean pronoun instead of preposition? It is normally regarded as an object or a subject pronoun.

[5jj]

Yes, shannico, John made a rare slip there. 'It' is indeed a pronoun, and the sentences with it are fine.

[JohnParis]

My apologies shannico, and to everyone else.
You are absolutely correct - I was wrong.
"It" is, indeed, a pronoun.
TGIF

[shannico]

I make plenty of slips. I hope you didn't mind me correcting you...
All the best.
Shan

[5jj]

I make plenty of slips. I hope you didn't mind me correcting you...

Anyone who posts in this forum, whatever their 'rank' does so in the knowledge that others can question/correct their answers; that is one of the great things about it.