The Jews present were "devout." They belonged to God and received the supernatural gift of interpretation of tongues. At this point in history, the gospel was only for the Jews, not to Gentiles until Acts 10. The mockers (God hates mockers anyway, Psalms 1:1, calling them ungodly and will perish) were probably Roman soldiers or Roman citizens.
Even today, not every 'Christian' is a believer, but more like mocking doubting Thomases, without faith, even calling tongues, 'gibberish'. Oh they may have faith in the written word, itself, but not in doing it, or that it is anything more than a 1st century history book; nothing that actually enriches their lives supernaturally. The Bible, "Sola Scriptura" becomes an idol and not understood. Some denominations are like the walking dead and Jesus in His letters to the seven churches of Revelation 2 and 3 tells some of them that if they don't repent, He will take their candlestick away; or leave them in Great Tribulation, like Thyatira, the RCC and Orthodox; saying to another "you have a reputation for being alive, but you are dead." That last one was the Protestant Reformation, 'Sardis.' Today, the Philadelphia church age are full gospel, "they have kept My Word," believing every part of our New Covenant is for them, and God blesses them richly. They do not twist scripture or become legalistically cessationist. They can literally hear God's voice, and do what He says. In fact, I don't pray for myself, unless God tells me what to pray, I say His words, and the prayer comes to pass immediately. John 15:7; 1 John 5:14-15; 1 John 3:21-23.