Hi - first of all please don't use Issue tag for problems with your solution; it is reserved for serious problems with the kata itself. You can use Question tag instead, that's its intended use.

Secondly, I have used your current solution on the 3 simple fixed tests and it fails on 2 of them:

# FIXED TEST 2: input string is "No offense but,\nYour writing is among the worst I've ever read"
"Yur wrtng s mng th wrst 'v vr rad" # <--- your solution returns this for test 2; note the 'u' at the start and the 'a' at end

# FIXED TEST 3: input string is "What are you, a communist?"
"Wht r yu,  cmmnst?" # <--- your solution returns this for test 3; note the 'u' near the middle

maybe you are missing these small errors on your phone when you say it seems to work fine, but it's actually making a few errors in the final result as you can see.