where in the bible does it say speaking in tongues is a heavenly language?
First, we should point out that the expression “heavenly language” is nowhere found in Scripture. Also, the phrase “tongues of angels” is used only once, in 1 Corinthians 13:1, “If I speak in the tongues of men or of angels, but do not have love, I am only a resounding gong or a clanging cymbal.”