1. Speaking in unknown tongues means to speak by the power of the Holy Spirit in languages unknown to the mind of the speaker, Acts 2:4
2. Some Christian denominations don’t believe in speaking in tongues as an initial sign of baptism of the Holy Spirit because there are many misunderstanding about the subject, Acts 19:1-2
3. It is possible for the speaker in unknown tongues not to understand what he’s saying, 1Cor 14:14
4. The speaker in unknown tongues speaks to God and not unto men. But it is possible for God to send messages in unknown tongues to some people; and in such cases, there would be an interpreter to interpret divine utterances to understandable human speeches, 1 Cor 14:2
5. The hearers of unknown tongues may not understand what is being said. But in few occasions, and to act as a sign, God may allow the hearers to understand what is being said in unknown tongues, Acts 2:4-11
6. A believer who speaks in unknown tongues may only be able to understand with his spirit because the speeches are supernatural, 1Cor 14:11
7. Speeches in unknown tongues may be interpreted if there is a believer who is gifted with the gift of interpretation of tongues. Whenever God permits this, it is for the benefit of the hearers, 1 Cor 14:9-11
8. The speaker in unknown tongues speaks as the Holy Spirit gives utterance, 1 Cor 14:2-4
9. ‘Speaking in unknown tongues’ is sometimes referred to speaking in the language of angels, 1Cor. 13:1