I want to make sure I understand what you are saying and what I also said is understood. I did not say that tongues prove this existence of God. The letter to the Corinthians where the word tongues are being used found in Chapter 12 through 14 must be seen contextually with why they are even being mentioned. The word tongues in 1cor chapter 12 where it is used first are listed as one of the "Gifts of the Holy Spirit". Context is not the organ of the mouth but something that is being done in the believer by the power of the Holy Spirit. Yes the word "tongues" is speaking about languages and yet the context does not end with Chapter 12, does it? Because we have Paul speak about what is called "UNKNOWN" tongues too in chapter 14. You say foreign languages yet the word foreign is not used but unlearned is or Unknown. the word Translator is not used either. but the interpretation is, which is not a translation.1. So you are stating the tongues proves the existence of God?
2. Glossa" (glwssa), which is the word used to designate the languages discussed in the letter to the Corinthians, means either the tongue (the physical organ in our mouth) or a language accessible to human understanding such as a foreign language, but not the phenomena such as glossolalia. Therefore the issue at the church of Corinth was the existence of foreign languages within a congregation and how they should be managed, a translator was required otherwise they were to keep silent, this was not the gift in Acts of the Holy Spirit.
tongues is proof of God existence? No. Are tongues one of the gifts of the Holy Spirit where HE uses the believer in? Yes. Are the gifts does to show God is working in the life of the believer? Absolutely yet tongues is not the only gift which does that.