Nope, not a typo. I totally missed that. Thanks a lot for noticing and correcting. The word SO makes the word adept get more emphasis on its meaning. I also agree to using "the English" rather than "English" alone. I learn as I go and I honestly appreciate your comments. I actually need more people like you to qualify and verify what I am trying to say here.

I am not editing the sentence in question and let's see who else will share their ideas.

Learning never stops. Thanks for your kind words, too.