Where should the word “probably” be placed

Consider the following sentences:

1. I'll move to the south by then probably.


2. I'll probably move to the south by then.


3. I'll move to the south probably by then.

Which of the three is correct. In my opinion, the third one is wrong. First two are correct with a small difference in their meaning.

First one makes my probability refer to the time when I'll be moving and the second one tells that there is still a chance that I might not move.

Am I correct?

Answer

Although normally called an "adverb", probably is often used to modify an entire sentence - in which case it normally appears at the beginning (or the end, if it's "parenthetically" added after a comma)...

a: Probably I'll move to the south by then.
b: I'll move to the south by then[,] probably.

---

In other contexts, syntactically it's more like an adjective than an adverb, in that it normally modifies the immediately following term...

c: I'll move probably to the south by then.
d: I'll move to probably the south by then.

Both of these imply that you will have moved by then (possibly to the north, but most likely to the south).

---

e: I'll move to the south probably by then.

Implies that you will move to the south (possibly much later, but most likely "by then").