The main context here is to not be ignorant of spiritual gifts, not to be led away by deceiving spirits but rather be led by the Holy Spirit.  But then there’s verse 3:

Now about the gifts of the Spirit, brothers and sisters, I do not want you to be uninformed. You know that when you were pagans, somehow or other you were influenced and led astray to mute idols. Therefore I want you to know that no one who is speaking by the Spirit of God says, “Jesus be cursed,” and no one can say, “Jesus is Lord,” except by the Holy Spirit” (1 Cor 12:1-3).

Can someone who is not of God say the words “Jesus is Lord”?  Absolutely.  We see the demons mocking Jesus himself.  So it’s not about saying the exact words.  We partly imply this because the translators have added the quotation marks, seeming to indicate that it is about the exact words.  Now take out the quotation marks.

no one can say Jesus is Lord except by the Holy Spirit

This is much deeper and beyond just words.  It is how one is living.

Is it acceptable to use quotes?  Yes, because even though it does not appear in the Greek, it does seem more of a confessional statement.  The problem is that English readers have a very strong way to interpret quotes as the literal, actual, words.  And while that may be somewhat true in the confessional sense, the Biblical sense is not just words, but about life exemplified in action.

No one can truly claim to be of the Holy Spirit and not keep Jesus as the central part of their lives.  Those who are of the Holy Spirit will not just declare but also live with Jesus as the center of their lives.

But how does this all relate to spiritual gifts?  Because that is the context.

In the past, when influenced by idols, those idols were mute.  They were wood, stone, and silver.  They could not declare Jesus as Lord.  And yet, the people were influenced by them.

The Spirit however is part of the Logos, the Word.  And the Spirit is not mute.  Those who are of Christ live and declare the Lordship of Christ with their mouths and their lives.

The Holy Spirit is the source of the gifts.  He is the third of the Triune God where gifts flow from.  And if you look, the gifts that are represented in this particular passage are gifts that involve communication/speaking.

Does it mean someone who is mute cannot have the gifts?  Not at all.  God gives gifts to everyone.  They just have to communicate differently.  Just like when two people come together who speak different languages, communication can still happen.  That can’t happen with idols of wood and stone.

So no, this is not a verse saying no one can say the exact words “Jesus is Lord” if they are not a believer.  But it is indeed about one’s life and declaration that is rooted in the Spirit.