off vs leave vs vacation

Hello

Would you please tell me which one of the following sentences is good English and is commonly used?

1-I have two weeks off.
2-I am two weeks off OR I am off for two weeks.
3-I have taken two weeks off.
4-I’m on leave for two weeks.
5-I have two weeks of vacation.
6-I have taken vacation for two weeks. OR I have taken two weeks vacation.
7-I’m on vacation for two weeks.
8-I’m going on vacation for two weeks

Thanks a lot.

.
These:

1-I have two weeks off.
2-I’m off for two weeks.
3-I’ve taken two weeks off.
4-I’m on leave for two weeks.
5-I have two weeks of vacation.
6-I’ve taken two weeks’ vacation.
7-I’m on vacation for two weeks.
8-I’m going on vacation for two weeks.
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