Paul discusses two types of tongues: those of people and those of angels (13:1). When someone speaks in the tongues of angels, they are speaking to God (14:2)—no one else understands them and thus they need an interpreter (14:28). When someone speaks in the tongues of people, they are miraculously speaking to someone in their own language, without training (Acts 2:3–4, 11). Compare 1 Cor 13:8; 14:4–33. (Faithlife Study Bible)