plugger, I am in no way offended. I hope I didn't offend you. From what I have learned, people can and do (through the Holy Spirit) speak in other known languages to people. Sometimes the person speaking in tongues understands (interprets) what is being said and sometimes the person has no idea what they are talking about, although they are speaking fluently in another language.
And a person can speak in unknown tongues and only a person with the gift of interpretation can interpret what is being said. It may be the person who was talking or it may be another person who interprets.
Speaking in unknown tongues has been used in intercession for others who are in danger. I do not have a Bible verse for this. But I have heard of it many times.
When you speak in tongues, you edify (to instruct or benefit, esp. morally or spiritually; uplift) yourself. (1 Cor 14:4 He that speaketh in an [unknown] tongue edifieth himself; but he that prophesieth edifieth the church.)
Please ask me anything you want. I will be glad to help if I can or I will try to find an answer for you.