English Translation
Tom couldn’t speak French when I first met him.
This is an interesting subtlety and a good case study for umieć/ potrafić.
Umieć would usually be used for knowledge of a language and in this context is also fine, implying that he just hadn’t learned it.
The use of potrafić here is interesting, because it suggests he may have some knowlege of French, but the action he is not capable of performing is the actual speaking of the language itself, whether it be due to nerves or struggling with verbalising the sounds.