That's part of the problem we're having with this thread. The question has been asked several times "What is 'it?'" There are a number of different versions of what tongues are--and most of them have appeared in one or more of the posts in this thread.
When an objection is raised on the basis of Scripture or anything else, the most common response seems to be "That's what those other Pentecostals do." Well, "it" has to be something specific. It cannot be that tongues ceased, but they did not. It cannot be that tongues-speaking is a private prayer language and at the same time something that needs a translator. It cannot be that we're talking about real languages that are otherwise spoken somewhere on Earth...or that it's purely a 'spiritual' language. It cannot be that it's intended as something that will lead to the conversion of non-believers...or that it's just something done in certain churches on Sunday for the benefit of those assembled there. Each time that it's shown that Scripture doesn't support one or another of these theories, the "real" tongues-speaking is supposed to be something else.
I'm not looking to endlessly dodge the issue - sometimes the truth of the matter is that some people regard a behavior as acceptable or normal when I'd say it isn't (and chances are it works the other way too).
I don't see a problem with tongues as a private prayer language - although Rom 8:26 doesn't clearly and explicitly say we may speak other languages I don't see a problem with it supporting the idea that sometimes we pray for something that we can't put into words, in some other way. Whether that other way be a succession of pictures in our heads, concepts, another language isn't something I'd get too worried about.
On the other hand tongues when spoken out loud in a group setting would seem to fall under the covering of 1Co 14:28, which also supports the idea of tongues as a private language. If someone speaks there should be an interpreter and if no interpreter is forthcoming the person should speak to himself and to God. No sense that he should no longer pray in tongues, merely that he should no longer pray in tongues such that the church can hear him.
I don't see a reason why a gift of tongues may operate in a manner that the speaker doesn't even know it's going on. Is there any reason why God shouldn't allow two people who hear a speaker, to hear in their own native language? We tend to focus on what sound comes out of the speaker's mouth but why should it be heard the same way by everybody? On that basis tongues could lead to the conversion of non-believers, if they hear the gospel in their native language even the speaker was using their own language.
To be clear, I think the churches where just about every prayer you'll ever hear just sounds like a load of gibberish have missed the mark (I've been to a couple of those). I would be concerned if people think that their own native language is somehow inadequate for the majority of their prayers because I would suspect, for most of us at least, we can put our prayers into words at least most of the time. I remember a couple I knew some years ago who, from what I gather, would routinely "pray in tongues" when doing things like merging from a slip road into heavy traffic. I was never sure why they felt the need to pray in tongues given that "Lord, please provide a space" would seem to express the request perfectly adequately.
I suspect part of the problem, as with so much other discussion on spiritual gifts, is that there tends to be a divide between the stances "God always..." and "God never...". If a Scriptural conclusion is that tongues have ceased then it logically follows that every single instance of someone speaking in tongues (assuming they have no natural knowledge of the language in question) is at best gibberish and at worst demonic. If a Scriptural conclusion is that tongues have not ceased it does not logically follow that every single instance of someone speaking in tongues is manifesting the Holy Spirit - they may still just be making up a bunch of gibberish to look more spiritual, they may be speaking a demonic tongue etc.
