Speaking in Tongues

Speaking in tongues means to "speak in different languages", e.g. speaking fluent Greek without knowing the language.

And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance. And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven. Now when this was noised abroad, the multitude came together, and were confounded, because that every man heard them speak in his own language.
- Acts 2:4-6 (KJV)

There is a strong focus to speak in 'tongues' in modern day churches, but it sounds more like "bla bla bla", and the people speaking it, can not explain what they just said. Very dangerous.

It is my opinion that the things that are actually being said, are more like insults to God.

Even when you speak in a different language, you will still need someone to interpret.

If any man speak in an unknown tongue, let it be by two, or at the most by three, and that by course; and let one interpret. But if there be no interpreter, let him keep silence in the church; and let him speak to himself, and to God.
- 1 Corinthians 14:27-28 (KJV)

Be very weary of the "speaking in tongues" that is being taught in churches today.