こんにちは
昨日私がCURE-DOLLYの3番目ビデオを見ました。「は/が」についてす。彼女は「私は○がさくらにボールを投げる」と「ボールは私がさくらに○を投げる」の意味が同じいです、と言います。
「さくらは、私が○にボールを投げる」は、意味が同じいですか。
In case my question is not clear: cure dolly says that modifying the noun marked by は does not change the logic of the sentence. Does my last sentence convey the same meaning (or at least the same Logic, ‘I throw the ball to Sakura’) ?
What’s with the ○?
私はさくらにボールを投げた
ボールは私がさくらに投げた
Are two sentences that express the same event happening and I’m guessing is what you’re trying to say in Japanese.
While they describe the same event, they do so with slightly different nuance. I guess if that counts as not changing the logic of the sentence, then sure?
It’s a bit unclear to me what the ○ in this sentence is indicating.
さくらは、私にボールを投げる = As for Sakura, she throws the ball to me. (The direct translation, “as for Sakura, to me throws the ball.”)
さくらは、私がボールを投げる = As for Sakura, I throw the ball. It does not specifiy a recipient of the ball, so the 「さくらは」element becomes confusing and doesn’t connect to the rest of the sentence in meaning.
Being a non-logical topic particle, 「さくらは」didn’t effect how 私がボールを投げる works as a sentence, but the particle usage also does not convey her as the recipient of the ball.
Cure Dolly’s way of highlighting that grammatical elements like subject and indirect object still play a part in the meaning of the sentence even when the words themselves (and attached particles) have been omitted.
It’s indicating that さくら would have been there had she not also been playing the role of the topic.
Seems silly and I still don’t understand but maybe that’s just me being stuck in my ways.
Since CureDolly was my foothold into grammar, I should probably have grasped this, but it has been so long now. 
I guess Cure Dolly doesn’t make it clear to learners that anyone who is unfamiliar with Cure Dolly specifically is going to be confused by that.
Indeed, you have to watch the video to understand what this means.
さくらは、私がボールを投げる
My Japanese is not good enough to be certain, but I really don’t think that’s a good way to say “I throw the ball at Sakura”. Or at least it would require a very specific context to make it make sense IMO. If I read that in the wild I would be very confused as to what the meaning could be.
Google translate and Deepl also struggle with the meaning, translating respectively:
Sakura said, “I’ll throw the ball.”
Sakura, I’ll throw the ball.
ChatGPT also struggles with the sentence and calls it “unnatural” and “ambiguous”. I wouldn’t trust blindly trust ChatGPT but it generally does decently for pure translation.
Modifying a sentence modifies the sentence. If you change the sentence then, usually, the meaning of the sentence changes.
You can split hairs like Cure Dolly and insist on classifying は as a completely different thing from が, but in practice this is kind of a pointless exercise IMO. Just read and listen to Japanese a lot and get a feel for how the particle are used and not used.
I sincerely do not understand the point Cure Dolly tries to make with this argument. Maybe it’s just to convince the watcher that Japanese is a “PERFECT LANGUAGE MADE OUT OF PURE LOGIC AND MATHS” because she has a tendency to fetishize the language, but practically speaking I just don’t see how this improves your ability to understand or speak Japanese.
I’m at the very beginning of my grammar journey, so forgive me for asking a silly question. Can you chain particles? さくらには、私がボールを投げる。Something like: Regarding to Sakura, it is me who throws the ball?
You can chain certain particles in certain orders yes.
には is ok
には is fairly common, it usually emphasizes that it’s specifically for somebody and nobody else. “I send the ball to Sakura (and nobody else, specifically her)”.
違いです。
でも、「さくらには私がボールを投げる」とは同じ意味ですよ。
Only が and を are omitted when used with は (and も).
All other particles, you need to keep them when attaching は (or も).