1 CORINTHIANS 14:2-4 (NLT)
"For if you have the ability to speak in tongues,a you will be talking only to God, since people won’t be able to understand you. You will be speaking by the power of the Spirit, but it will all be mysterious. But one who prophesies strengthens others, encourages them, and comforts them. A person who speaks in tongues is strengthened personally, but one who speaks a word of prophecy strengthens the entire church."
Unless there's interpretation tongues is for YOUR personal benefit. It literally strengthens YOU personally. So speaking in tongues is a good thing! And notice that only God knows what you're saying. However the only way it helps someone else is if there's the gift of interpretation in operation or if you end up speaking in an earthly language like is shown to happen in the book of Acts chapter 2.
So if you're feeling spiritually weak let Holy Spirit strengthen you by speaking in tongues! If you never have then ask Holy Spirit to fill you so full to overflowing that it just gushes out of you!