Swap two characters

I am a bad typist. I often hit the wrong keys on my keyboard. I never learned to type using 10 fingers, I only use one finger a time. The faster I type the more errors I make. It turns out however, that two kind of errors show up most frequent.
The first error concerns hitting the wrong key. Most often I hit the key next to the key I want to press. I have to go back to the position have to delete the character and retype the correct letter. I cannot speed up this kind of restoring.
The second typing error I often make is hitting keys in an incorrect order. An incorrectly spelled keyword in GFA-BASIC 32 marks the source code line in "error-state" after hitting [Enter]. That is the moment I realize I mistyped something. For instance:

Locla Bool fCommentLine

This kind of error is very easy to correct. Put the caret between the l and the a and then hit Ctrl-T. This swaps the two characters at either side of the caret.