The implication of 段々 with a non-past verb (なります)

Question

A sentence from my current favourite bugbear:

息子の成績が段々よくなります。
My son's grades are getting better and better. (given translation)

I have two problems with the given translation:

1. "getting better and better" implies that the grades were good to start with. This translation sounds like the parent is showing off; "My son was already great but now he is even better still". Whereas, I feel that the actual meaning should be more like 'gradually improving' i.e. the grades were previously unacceptable but they are becoming better. What is the actual, natural interpretation of this sentence?

2. I'm not sure how 段々 and なります interact with each other. To me this seems like it ought to be a future sentence i.e. "My son's grades will gradually become better (but they haven't yet). I want to use なっています、or something involving the auxiliary くる (but I'm never comfortable making my own sentences with くる so I'm not sure about that).

So, is this sentence natural for the meaning given in the English translation? If not, how would you make a Japanese sentence that better matched the English translation?

Answer 1

I would translate the given English translation back to Japanese as:

息子の成績がどんどんよくなっています。

I mostly agree with you on both #1 and #2 about the original Japanese sentence. It should be understood as “My son’s grades will gradually improve.” The current grades obviously have room for improvement but the sentence doesn’t say anything that indicates they are “unacceptable”.

I wonder under what circumstances a parent would give such a prediction about their son’s grades…

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Let me add this. if you want to express the meaning of 段々 (gradually), rather than どんどん (more and more, in an accelerating manner), you could say:

息子の成績が段々よくなってきています。

with the auxiliary くる. It sounds more natural to me than 息子の成績が段々よくなっています.