Speaking in tongues is a special gift gotten from the holy spirit. In the Bible the disciples of Jesus Christ received the holy and they all started speaking in different languages. It is a unique language which people use in communicating with God. Anyone speaking in tongues means God is using them to spread his words.
They are different types of tongue which we speak. We have the human language and the one holy spirit infest in us. The one of the holy spirits is only understood by God, even the devil doesn't understand it. Apostle Paul in the bible said speaking in tongues strengthens our relationship with God.
The bible also teaches that speaking in tongues is not for all the believers. It is a gift which we get from the holy spirit. What matters is the good life you're living. Do good to others and love your neighbours.