Hello Michaelting: The adjective 'proficient' means competent or skilled in doing or using something. I too have seen "proficient" used to describe one's ability to speak and write a language. This may come from a old and rare use of 'proficient' as a noun : He became a proficient in Greek and Latin.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.