No. If I had said, "...it is written specifically for the purpose of..." that would imply intent. I was speaking of the final result - a text that cold be read and understood. Pardon me if my wording didn't reflect that.
That being said, the intent of the author is not mentioned in the spell description, so I personally take it to be irrelevant.
Yes. You said it was written "specifically so" - the use of "so" there is understood to mean "for the purpose of"; changing the grammar used, in this particular regard, doesn't change the meaning of what you stated previously.
Now, if you want to abandon that particular line of reasoning, that's fine, but don't say that you weren't using it in the first place.
The spell description says that it allows you to "read otherwise incomprehensible messages". The spell explicitly falls short of being able to deal with you changing the meaning of the words, but the manner of writing it down seems to be irrelevant in the spell description.
You're stepping into a problematic area by saying "you changing the meaning of the words," since you're not specifying how you do that - indeed, the issue of assigning meaning to something you write can be based around nothing more than the intent of the author at the time of writing. As
Humpty Dumpty observed:
'When I use a word,' Humpty Dumpty said, in rather a scornful tone, 'it means just what I choose it to mean — neither more nor less.'
So the idea that the spell falls short by you "changing the meaning of the words" is clearly not true, since that gets back to the area of intent, which you've already said you weren't arguing to begin with.
Likewise, writing something down does matter to the spell description, since it says it can't break codes, so that's hardly irrelevant. Indeed, the
spell description says that it does not reveal messages "concealed in otherwise normal text." It's entirely possible to understand that part as meaning that it wouldn't make a transliteration comprehensible, since using one alphabet could be considered "normal" text, and using it to sound out foreign words could be concealing their meaning (since they have no meaning in the language(s) that alphabet is normally used in).
You can, of course, do whatever you want in your own game. I'm just going by the basic spell description.
It's more correct to say that you're interpreting the spell description, and that your interpretation is no more or less correct than anyone else's. You should feel free to use that interpretation, though; you can, of course, do whatever you want in your own game.