Nope, it is not unfruitful. Yep, God gave us his word to we would be able to know him. It is written: Speaking in tongues - edifies the individual (1 Cor. 14:4) and in a group, when interpreted, it edifies the church (1 Cor. 5b). The purpose of language is communication - It is written: When one speaks in tongues, he is speaking to God (1 Cor. 14:2), when one speaks in tongues and interprets - he is communicating to the church and therefore speaking words via the gift of holy spirit to edify the church (1 Cor. 5b). The Holy Spirit (God) gave us the gift of holy spirit to teach us, to guide us, to comfort us (John 16).
No need for mysterious sounds as secret words. Words have significate meaning attached to them, even the metaphors have the spiritual unseen meaning attached. If God would hide the meaning he who give us a parable. Not a grunt or a noise without meaning like children banging kettles with a wood spoon .
There are, it may be, so many kinds of voices in the world, and none of them is without signification.1 Corintihain14.
We must be careful on "how" we hear God. The verse is not declaring that it is a blessing to edify oneself a source of pride. Or as some say self-appraisal conforming something outwardly (good job)
Its God who prophecies' bringing His word in many languages other than Hebrews alone. God edifying, glorying his own self. A God whose name is Jealous. He speaks prophecy to men as the comforting word of the Holy Spirit
But he that prophesieth speaketh unto men to edification (of God the speaker the one doing the work ) , and exhortation, and comfort. He that speaketh in an unknown tongue edifieth himself; (not a blesssing) but he that prophesieth (speaking the word of God )edifieth the church.(the blessing)1 Corinthians 14: Two or three not one , and I will be in the presence
He that speaks in a language unknow to others edifieth himself (not a blessing) But he that prophecies( brining the word of God where two can understand each other) edifies the church .The church where two or three are gather together under the prophecy of God word . Not where one gathered together . All un seen spiritual gift are two fold . Not by the will of man but men that God moved according to the good pleasure of His will that works in men to both will and perform His good pleasure
There are, it may be, so many kinds of voices in the world, and none of them is without signification. Therefore if I (Paul) know not the meaning (of the strangers voice), I (Paul) shall be unto him (the stranger) that speaketh a barbarian, and he (the stranger )that speaketh shall be a barbarian unto me (.Paul)1 Corinthians 14:10-11
Today they have real time devices that allow to different language to be spoken and by the device each man hears what the other is saying in their own language. Neither are barbarians to the other. In that way Paul on his mission of visiting many other nations was not crippled but was successful at getting the gospel out.