grammar - Can "presently" and "currently" be used interchangeably?

Can "presently" and "currently" be used interchangeably?

For example which is better:

I am presently teaching Grade 12 or I am currently teaching Grade 12 ?

Answer

In British English, presently can mean at present. This doesn't appear to be the case in American English, where it seems it always means "shortly". Presently can have that meaning in British English, too.

The position of the adverb is used to distinguish the different meanings in British English. If presently occurs at the end of the clause, it normally refers to a future situation.

I am presently teaching Class 6B.
- This is taking place now.

I am teaching Class 6B presently.
- This is likely to indicate a situation in the very near future.

I will be teaching Class 6B presently.
- This is unequivocally describing a future situation.

There is still some ambiguity about the second example because although the "present tense" of be can be used to indicate a future state, and the position of the adverb indicates that it is referring to the future, I am is still the present tense and presently could mean now.

Currently always means now.