So I had come to the conclusion that the sentences
'私はボールを投げる’ and ’ボールは私が投げる’
meant functionally the same thing with different emphasis, literally ‘as for me, I throw a ball’ v.s. ‘as for the ball, i throw it’.
I asked about it on HiNative and someone (apparently a native speaker ?) said the 1st sentence meant ‘I throw a ball’ whereas the 2nd meant ‘I will throw a ball’.
I’m really confused now, are they right? Do they mean the same thing? (Are the sentences even right?) Even a link or something so I can read more about it would be greatly appreciated. Thank you!!
は and が can have a variety of meanings, and so it’s both true to say that the sentences can mean essentially the same thing… or that they could mean subtly different things… but in a vacuum it’s not really a meaningful discussion. They would need surrounding context to make the nuances, if they did exist, actually apparent.
が is the generic, neutral subject marker, but it can also be used for emphasis. So 私が could just be indicating a neutral subject, or it could be emphasizing that it is “I and not anyone else” who will do some action. Whether one interpretation makes sense over the other isn’t usually going to be clear from a sentence as basic as this, though you can imagine cases that are more or less likely to actually be used by real people.
Getting into all the ways は and が can be used is a huge ordeal, so I would recommend looking more into them over time and not worrying about absorbing it all in one go.
I would also caution you against taking things like HiNative answers as definitive unless they are pointing you to some kind of source. They can be a helpful starting point. Here they indicated to you that these sentences could be interpreted differently. But unless a person has training in teaching Japanese as a foreign language, or they’ve studied Japanese as a foreign language, it might be hard for them to explain exactly why they think the two sentences could be different.
OK, thank you! That explains my confusion.
As for HiNative yeah, I feel like it isn’t really a good place to actually learn grammar, I was just looking for a confirmation but I guess it isn’t that simple…
As a professional translator (I know I’m level 4, I just restarted Wanikani lol), maybe I can be of assistance.
First of all, take my explanations with a grain of salt. If they help you, that’s awesome! If they just confuse you more, forget I ever said anything. I’ve been studying Japanese for years, so I’m sure a lot of things sound like real explanations to me even though they don’t make sense to people early on in the process.
Basically, the person who answered you on HiNative wasn’t wrong, but they also failed to tell you that, technically, both sentences could mean either. They just gave you what they would more commonly be interpreted as without context, as you wrote them.
Hmm… How to explain.
To me, 私はボールを投げます sounds like a sentence you would find either in a children’s book, a textbook, or a set of instructions. Think about it this way. Just as you wouldn’t say “I throw the ball” except under those very specific circumstances in English, so you wouldn’t in Japanese. “I throw the ball” would be a pretty common sentence to find in a textbook, or maybe to hear from someone explaining how to play baseball, but you wouldn’t normally hear it outside of that context. That’s probably why your HiNative helper said it sounded like the present tense.
The present tense in most other cases, though, would be “I’m throwing the ball(私はボールを投げています)”. Because the present tense can also be the future tense in Japanese, many sentences in the です/ます form or dictionary form can also be taken to be in the future tense depending on context. Therefore it’s a bit of a game of elimination. If “I throw the ball” sounds weird in context in English, then by process of elimination and by context clues, it would actually likely be in the future tense: “I’ll throw this ball”/“I’m going to throw this ball.”
This is even more the case for ボールは私が投げます.
In English, you would never say the sentence, “This ball, I throw it,” or even “I throw this ball (in particular).” What you WOULD say is “This ball? I’m gonna throw it.” Since 私 takes the が particle, that means it’s the focus of the sentence. Who’s throwing the ball? 私. You would generally only need 私 to be the focus of the sentence if who was throwing it was under contention (“I’m gonna throw it. No, I’m gonna throw it!”). If you think about it, there are very few circumstances in which you would need to specifically emphasize who’s throwing the ball in those very specific circumstances I mentioned earlier. You could, and in those cases it would be fine to use このボールは私が投げます to mean “I throw this ball,” but without context, and in real life, it’s more likely that maybe people are fighting over who’s gonna throw the ball, which would make the sentence future tense.
Does any of that make sense?
Just to be clear, I don’t recommend comparing with English grammar for all things, but in the case of present vs. future tense, I often find it helpful to think about the context. If it would be future tense in English, likely it would be future tense in Japanese.
tldr: Either sentence can mean either, but both are more likely to mean the future tense outside of a textbook or set of instructions.
Hope this helps even a little bit, and sorry for the long-winded, confusing explanation!
I feel like this is probably well-enough covered above, but situations I’d imagine for the different variations:
(私は）ボールを投げます - “I’m going to throw the ball,” like, immediately. “I’m throwing the ball (now, like near-immediate future).” Announcing you’re about to do it. Get ready! Here comes the ball! (I wouldn’t expect an explicit subject to be used here at all really; it’s very text-booky with one.) The emphasis is on your action. It could also be a response to someone asking you what you’re going to do in a game/practice, I suppose. “Me? I’m going to throw the ball.” (In that case it probably would have the explicit subject; that’s the only scenario where I can actually imagine that exact sentence being used.)
ボールは、私が投げます - Planning roles for practice/a game. “Okay, I’ll throw the ball.” (As in, someone is going to be on ball-throwing duty, and it’s going to be me. You’ll be in charge of something else. But we all know there’s a ball and someone’s going to be throwing it, and we’re clarifying who now.)
Both future tense, but one basically simultaneous with the action (probably), and the second for advance planning.
…'tis the nuance anyway, and what probably led to your different HiNative answers.
Whatever is marked by は is emphasized or a/the expected topic of the conversation. が follows strictly grammatical subjects or new topics you don’t want emphasized.
バスはあと5分で来る - The bus (that we both know is coming and have been waiting for) will be here in five minutes.
バスがあと5分で来る - There’s a bus coming in five minutes. (As an aside or new subject that isn’t the focus of conversation. Would probably segue into another thought like, “So we should probably get out of the middle of the street.”)