UPDATE: Based on the discussion below, I now see that my proposal is not valid. But still, I want to make a clarification about the following proposal, anyway. Just please keep in mind that I'm keeping this modified version of the original question here simply for reference, and not to assert that it's correct, because I now know that it indeed is not nearly as correct as I was hoping.
I'm changing my original question below by replacing "indefinite/definite article" with "indefinite/definite modifier". Such a "modifier" could be an article, an adjective, or even an adjectival phrase. In "some cats like fish", "some" is an indefinite modifier. The same is true with simply "cats like fish", in which the lack of a modifying word or phrase is a plural manner of indicating indefiniteness, and in this case, no modifier is an implied indefinite modifier. Likewise, in "those cats like fish", "those" is a definite modifier. In my proposal (which, again, I now realize is indeed not valid), replace references to "A" and "THE" as follows ...
MODIFIED ORIGINAL QUESTION:
Japanese speakers (and other non-English speakers) sometimes get confused about when to use
the article "THE" a definite modifier (one example being "THE") in English versus the article "A" an indefinite modifier (one example being "A") in English. Likewise, English speakers sometimes get confused about when to use the particle は versus the particle が in Japanese.
An idea occurred to me recently which might be able to link the use of these English
articles modifiers with the use of these Japanese particles. I'd like to explain this idea, and then I'd like feedback as to how valid this idea of mine might or might not be.
Suppose that you and I are having a conversation, and you ask me what I'm doing tomorrow. If I was speaking English, I might say, "A friend asked me to lunch tomorrow." But if I want to tell you this in Japanese, I believe that it would be ...
ともだち が [asked me to lunch tomorrow]
(I'm sorry, but my Japanese vocabulary knowledge is weak, but the translation of "asked me to lunch tomorrow" is not pertinent to what I'm asking about here, anyway).
Then, suppose you follow up by asking me, "Oh, what restaurant are you going to?"
I might respond as follows in English: "The friend likes to cook. We'll be eating at home." In Japanese, I believe that would be ...
ともだち は [likes to cook. We'll be eating at home]
(Again, the translation of "likes to cook. We'll be eating at home" is not pertinent to what I am asking about here.)
Notice that in my first sentence, the English is "A friend" (which uses an indefinite modifier), and we use が in Japanese. And in my second sentence, the English is "THE friend" (in which we use a definite modifier), and we use は in Japanese.
So, would it be safe to say that if we are correctly using an indefinite
article modifier in English such as "A" or "SOME" or no modifier at all in the plural case (which implies indefinite) to describe the subject or topic of an English sentence, then we would tend to use が in Japanese? And would it also be safe to say that if we are correctly using a definite article modifier such as "THE" or "THESE" in English to describe the subject or topic of a sentence, then we would tend to use は in Japanese?
And conversely, would it be safe to say that when が is correctly used for the sentence subject in Japanese, an indefinite
article modifier such as "A" or "SOME" or an empty implied modifier would generally be correct in English? And would it be safe to say that when は is correctly used for the sentence topic in Japanese, a definite article modifier such as "THE" or "THOSE" would generally be correct in English?
I know that this "rule" wouldn't work 100-percent of the time. However, it seems to me that it could work in at least many cases, and therefore, perhaps could it be a good mnemonic device for English speakers to help them decide when to use が and は? And likewise, perhaps could it be a good mnemonic device for Japanese speakers to help them decide when to use
"A" and "THE" definite or indefinite modifiers in English?
What are your opinions about this idea of mine?
And again, based on the discussion below, I realize that this original proposal of mine is not as helpful as I was originally hoping, and I'm only leaving it here for reference.