Stan, I don't really agree with the second part of your title.
For me, loneliness is more about the lack of bonds and connections with others. You can be a great speaker of several languages and still feel loneliness, because human communication goes far beyond words. Sometimes our body language says more than the sentences we pronounce. For a couple in love, a long, tender gaze into the other person's eyes is worth a thousand words.
I believe that extroverts can do better in acquiring speaking skills, because they are less shy and more comfortable talking with people in their target language.
Introverts, on the contrary, can be strong in reading and writing, activities that they can do when they are by themselves.
Do you feel like you are talking to somebody by reading and writing? If it's so, Stan's comment makes sense. You are not alone as long as you can read.