For one who speaks in a tongue speaks not to men but to God; for no one understands him, but he utters mysteries in the Spirit.
(I Corinthians 14:2)
Do you know that when you speak in tongues you are speaking mysteries.
A mystery is just a truth that has not been revealed to you yet.
Speaking in tongues can plow through the soil of your mind preparing it for revelation.
Now, think...does that mean every time you read the Bible, hear teaching etc you could be receiving more revelation than you do just by speaking in tongues?
Doesn't that make you want to speak in tongues more than you do?