Is there any strong backing in scripture for Christians that claim that speaking in tongues (Glossolalia) is the evidence of the infilling of the Holy Spirit, and necessary for Salvation?

I know this may not necessarily be the kind of question that is fully appropriate for a group like this, but I’m seeking more of an academical input on this subject without any of the religious / denominational biases. I hope this is okay.

I suppose this is a two part question, and forgive me if my language is a bit messy, as I am exhausted at the moment -

I understand that most scholars hold that “tongues”, as is mentioned throughout the New Testament in reference to the gift of tongues, can most likely be interpreted as translatable, Earthly languages. The tongues serve a purpose, and that purpose is to evangelize and spread the gospel to those who would not hear it otherwise.

I am also aware that there exists a minority of scholars that interpret “tongues” to mean a mix of “ecstatic, unintelligible utterances” (Glossolalia, similar to what we see in the modern Pentecostal movement), and translatable Earthly languages. This group of scholars will almost always point to the first account of tongues in Acts as an example of this, saying that the Apostles spoke in "ecstatic, unintelligible utterances”, which is why, for example, the crowd assumed that they were drunk.

What do you guys think? Do you believe that every instance of tongues in the New Testament is specifically referencing translatable, Earthly languages? Is there strong evidence to suggest otherwise? Is it a most likely a mix of both?

And for my second question -

Is there any passage in scripture that can even slightly give merit to the idea that speaking in tongues specifically is necessary for salvation? That it is the “initial evidence” of the infilling of the Holy Spirit? This is a popular idea that seems to be growing within modern Pentecostalism.

Many Christians who believe this interpretation will typically site Acts 2:16, Acts 2:38, Acts 10:44-47, and Acts 19:6 as proof texts to support this doctrine.

Any input is appreciated!