Speaking in tongues is a gift of the Holy Spirit.
I Corinthians 12:10 NKJV
 to another the working of miracles, to another prophecy, to another discerning of spirits, to another different kinds of tongues, to another the interpretation of tongues.
The person who speaks in tongues communicates directly with God. This is why I think the dream is a message from God.
I Corinthians 14:2 NKJV
 For he who speaks in a tongue does not speak to men but to God, for no one understands him; however, in the spirit he speaks mysteries.
I think this is a warning dream from God regarding the person you are to date. The felony, a serious crime, that is mentioned could be in regards to the person breaking man’s laws, and therefore a felony in the natural or the person broke God’s laws and committed a felony in the spiritual. I think you should pray about it and ask God to guide you in the choice of the person to date, and if you do come across this person who committed a felony, surrender them to God, pray for them, and do not date them. Heed the warning.