As stated, I am neither a cessationist nor a continuationist; I do not identify with either term. In fact I had never heard of either until just a few years ago. This seems to be 'born again Christian' nomenclature.
As far as the audience needing an interpreter, it's because no one there at that particular public gathering understands the speaker's language. The only person being edified is the speaker. Paul calls for clarity and understanding at a public worship setting such that all may benefit; thus, his calling for an interpretation so all may benefit.
1 Cor. 14:14-15 -
This one could easily take a few pages to explain properly, but I'll try and sum it up as briefly as possible.....
AS with Acts, you have to go to the Greek. This passage hinges on the Greek word “akarpos” – which can be used in two different ways: in an active sense and in a passive sense.
Many people subscribe to a passive usage, i.e. my understanding is unfruitful ( to me ), or my understanding produces no fruit in/for me . In short, what I'm saying doesn't benefit me as I have no idea what I'm saying even though I am praying “in the spirit” (as defined in my previous posts).
Given that Paul, in his letter, calls for clarity and understanding at a public worship such that everyone there can benefit, an active understanding of ‘akarpos’ makes considerable more sense in light of what Paul is trying to convey: that is, my understanding is unfruitful for others , or my understanding produces no fruit for/in others .
In other words, the fact I understand what I’m saying does not benefit anyone else as they don’t speak my language.
This is not just my view, but also the view of a number of Biblical commentators (Clarke, Barnes, Coffman, Gill, Vincent, Wesley, Abbott, Calvin, Coke, Meyer, Edwards, Schaff, et al.)
Now, before you think using this passage with an active meaning is something far-fetched, or a new concept, or a recent ‘theory’, consider Luther’s Bible of 1534 - written almost 500 years ago, and some 30 years before King James was even born.
This same passage is rendered (in English) “...my understanding brings no one fruit”.
Even almost 500 years ago, the idea of this passage having an active usage was nothing new. Indeed, an active understanding/reading fits better with Paul’s intent of clarity so all may benefit. Further, it's clear here the speaker is praying in a particular (known) language; his native language.
There’s just no evidence whatsoever of modern tongues-speech here. The speaker understands perfectly well what he’s saying; again, it’s the audience who doesn’t understand, and thus does not benefit.
Verse 15 - In this verse, the speaker will 'pray/sing in the Spirit' (as defined in my original post), and will pray with his mind/understanding. The context requires that praying/singing with 'his mind' is understood to mean with his mind bearing fruit or being fruitful to others. Again, the active sense as already defined in verse 14. It's all about real, rational language. One the speaker knows, one the audience does not.
Yes, in Acts, the Apostles were speaking real, rational language, but not nearly as many as most people suppose.