Not everyone can speak in other tongues or different languages that they have not studied but, everyone can speak in Tongues of Truth in their own languages.
To clear up confusion, it is a requirement to be saved to talk differently than the world but not a requirement to speak in other tongues or different languages to be saved. Jesus spoke Tongues of Truth but there is not one scripture reference of Him speaking in other tongues or different languages. Truth is all over the Bible, more than the gift of tongues. The only requirement to be saved is speaking in Tongues of Truth. The Bible speaks very clearly about telling the whole truth from every angle and aspect.
At least the principal of speaking in Tongues of Truth is in the Bible even though the direct phrase is not. While everyone has lied at some point in their life, a real Christian at least does not tell a lie every day of their life. Cross references to John 4 like John 7:39 and the cross reference to those point to Acts 2 about tongues. If Tongues in Acts is a cross reference to Living Water and true worshipers will worship the Father in the Spirit and in truth, then logic would say that Tongues of Truth is a biblical principal. I can speak in other tongues but I use it as my own private prayer language.
Based on the following scriptures
John 4:23, John 4:10
John 7:38,39 38 Whoever believes in me, as Scripture has said, rivers of living water will flow from within them.”[c] 39 By this he meant the Spirit, whom those who believed in him were later to receive. Up to that time the Spirit had not been given, since Jesus had not yet been glorified. Cross reference to verse 39 is
Acts 2:1-4;
Revelation 21:8 John 18:37
Painting of anointing oil for tongues of truth
16 by 20 inches