Well be careful of that. You are certainly free to believe as you wish, but the text is not talking about Isaiah speaking in tongues.
Sometimes, the so called popular understanding is the right one and context should not be tossed aside if the understanding is actually to benefit.
You would be hard pressed to provide context for tongues here. The translators have come to the conclusion that Isaiah is mocking those who mock his prophecies. This is not really a case that demands a different understanding or a case of just believe your own opinion.
Of course you are certainly free to think you have a different understanding just as others are free to point to context in this situation and the fact tongues came as cloven fire on the day of Pentecost and not as some hidden gem in an otherwise very pertinent and abrasive prophecy from a major prophet.
Sometimes, the so called popular understanding is the right one and context should not be tossed aside if the understanding is actually to benefit.
You would be hard pressed to provide context for tongues here. The translators have come to the conclusion that Isaiah is mocking those who mock his prophecies. This is not really a case that demands a different understanding or a case of just believe your own opinion.
Of course you are certainly free to think you have a different understanding just as others are free to point to context in this situation and the fact tongues came as cloven fire on the day of Pentecost and not as some hidden gem in an otherwise very pertinent and abrasive prophecy from a major prophet.
As to whether Isaiah was writing in tongues, no, I don't think so.
But if he was mocking their language by mimicking sounds, that can't be translated into words like "line upon line" then we should reevaluate the whole statement in that light.
If he is saying "their language will sound like nonsense to you" or if he is saying "You say that my words are like nonsense to you" either way he is saying "someone is making a reference to someone sounding like nonsense speaking meaningless words that we cannot understand."
Now some will insist that is not the case and these words actually mean "line upon line... etc." because they see them translated that way in most English translations and they will simply go with that and decide to teach something about how we do bible study.
I will not argue with them about it. I might say,. "I don't think that is what what means." but if they are not interested in re evaluting their position I would let it go.
After all it is true that we should study scripture and let scripture interpret scripture and all that they are trying to say using this verse misapplied so I am not going to press it.
Too many other things to focus on than trying to correct people every time they use this "line upon line" verse to teach bible study methods.
My only thoughts about it at this moment is that IF he is talking about how someone will think someone is speaking nonsense words, and since we KNOW that Paul did reference this text in context of speaking in tongues, then is it possible that contained within this prophesy (originally about Assyria or / how people misunderstood Isaiah (two possible interpretations mentioned by scholars) ) That there is a sensus plenior reference that unbelievers will accuse those who speak in tongues as saying senseless nonsense? And so it is today both unregenerate people and fellow believers who are skeptical accuse those who speak in tongues as speaking gibberish.
Like Isaiah by inspiration of the Holy Spirit not even knowing it went beyond the Assyrian invasion in prophesying a time when God would give the Church the gift of tongues and people would mock them and say "these men are full of new wine."