Paul said, "i want you all to speak in tongues" and "I thank God I speak in tongues more than all of you."
Paul adds "you can all speak in tongue" and "He who speaks in tongues edifies himself." So what are your waiting for? Or can Paul's spirituality b e safely ignored.?
Isa 28.11 is a reference for the definition of Tongues. Tongues is simply speaking a Gentile language. such as Egyptian or another Gentile language. That is why he was glad he spoke in many Gentile Languages, that is, Paul was evangelizing throughout the Empire by the use of his gift of speaking in Gentile languages (an example of Paul speaking in Gentile languages to the unbelievers. So, speaking in a foreign language is what Tongues primary purpose is all about (in today's terminology it is speaking in German, French, Japanese, etc.). Bear in mind that Paul said that Tongues is not for the believer, but for the unbeliever. That is the primary purpose of Gentile languages, and that is how Paul and Luke defined Tongues. In fact, the term "Tongues" would be better translated "languages." in today's usage. "Tongues" meant "languages" as it did in first century. Watch an old western movie that primary includes Indians, and the Indian will even say, "He speaks in white man's tongue." He simply means a Gentile language."
Remember, tongues/languages are primarily an evangelistic tool used to aid learning the foreign language, enabling a believer (for example) to speak Egyptian. When God wanted some believer to speak a foreign language, he likely will just give that believer that ability to speak (for example) in Japanese without having to learn it, God just gives him a second language to aid in spreading the good news of Jesus.
Finally, according to Heb 2:3,4
3 πῶς ἡμεῖς ἐκφευξόμεθα τηλικαύτης ἀμελήσαντες σωτηρίας, ἥτις, ἀρχὴν λαβοῦσα λαλεῖσθαι διὰ τοῦ κυρίου,
4 ὑπὸ τῶν ἀκουσάντων εἰς ἡμᾶς ἐβεβαιώθη, συνεπιμαρτυροῦντος τοῦ θεοῦ σημείοις τε καὶ τέρασιν καὶ ποικίλαις
δυνάμεσιν καὶ πνεύματος ἁγίου μερισμοῖς κατὰ τὴν αὐτοῦ θέλησιν;
3 how shall we (
2nd generation of Christians) escape if we ignore so great a salvation? This salvation, which was first announced by the Lord (
1st generation), was confirmed to us (
2nd generation of believers) by those who heard him (
1st generation believers). 4 God also testified to it by signs, wonders and various miracles (
1st generation of believers), and by gifts of the Holy Spirit distributed according to his will.