I'd like to live in France and fly out of a lovely grass strip I found, but I don't speak French. I would not be able to explain my intentions on the radio. You can not truly be part of a group if you don't know what the others are saying when they talk with each other.
Even if you are speaking in a language given to you by God himself, it's not good to use around others unless there is someone to translate it.
New American Standard Bible (NASB) 1 Corinthians 14:5-7 wrote:5 Now I wish that you all spoke in tongues, but even more that you would prophesy; and greater is one who prophesies than one who speaks in tongues, unless he interprets, so that the church may receive edifying.
6 But now, brethren, if I come to you speaking in tongues, what will I profit you unless I speak to you either by way of revelation or of knowledge or of prophecy or of teaching? 7 Yet even lifeless things, either flute or harp, in producing a sound, if they do not produce a distinction in the tones, how will it be known what is played on the flute or on the harp?
You can not become a Ger tzedek without learning Hebrew and memorising much of the Torah. How then could I be a Roman Catholic if I don't speak Roman and learn to read their Latin bible?