1 Corinthians 14:9

9Soοὕτωςalsoκαὶyouὑμεῖςwithδιὰtheτῆςtongueγλώσσηςifἐὰνnotμὴintelligibleεὔσημονspeechλόγονyou giveδῶτε,howπῶςwill it be knownγνωσθήσεταιwhat [is]τὸbeing spokenλαλούμενον;You will beἔσεσθεforγὰρintoεἰς[the] airἀέραspeakingλαλοῦντες.

So also you⁺, unless you⁺ give intelligible speech through the tongue, how will it be known what [is] being spoken? For you⁺ will be speaking into the air.