adjectives + narimasu


Good evening,

I've been studying Japanese here in Tokyo for about a month now in a Nihongo
Gakuin. One of the lessons that we encountered was adding adjectives +
`narimasu` like for example:

[code]

    osoi = osoku narimasu
    ookii = ookiku narimasu
    hayai = hayaku narimasu
    
[/code]

From what I understood it's changing the last `i = ku` in `i-adjectives` so it
becomes a noun, or simply adding `~ ni` to `na-adjectives`. Although, I was
wondering how that would apply to colors. For example, `akai`. Does it become
`akaku narimasu` or `aka ni narimasu`?

[code]

    しんごうはあかくなりました？ 
    しんごうはあかになりました？
    
[/code]

The traffic light became red. Any help is greatly appreciated. Thank you very
much!




In most contexts, the most natural way to say something “turns red” or
“becomes red” is by using あかくなります. For example, わたしのかおがあかくなりました would be one
way to say “my face turned red,” and you can also say そらがあかくなりました (“the sky
turned red”). The same pattern holds for other color adjectives that end in い
(e.g., そらがあおくなりました - "the sky turned blue").

However, for the particular example you’ve asked about – a traffic light – it
would be much more natural to use the noun form + に. I suspect that this is
because traffic lights don’t actually “turn red” at all, at least in the sense
that a face or a sky can turn red – what really happens is that an amber light
goes off, and a red light goes on. (Maybe they are really plain lightbulbs,
one behind an amber lens and one behind a red lens, but you get the idea.) It
may also be relevant that the Japanese term doesn't conflate the entire
apparatus with the individual light(s) that are part of it, as the English
term "traffic light" does. (しんごう is really closer to "traffic signal.") In any
case, it is far more usual to say しんごうがあかになりました.




In most contexts, the most natural way to say something “turns red” or
“becomes red” is by using あかくなります. For example, わたしのかおがあかくなりました would be one
way to say “my face turned red,” and you can also say そらがあかくなりました (“the sky
turned red”). The same pattern holds for other color adjectives that end in い
(e.g., そらがあおくなりました - "the sky turned blue").

However, for the particular example you’ve asked about – a traffic light – it
would be much more natural to use the noun form + に. I suspect that this is
because traffic lights don’t actually “turn red” at all, at least in the sense
that a face or a sky can turn red – what really happens is that an amber light
goes off, and a red light goes on. (Maybe they are really plain lightbulbs,
one behind an amber lens and one behind a red lens, but you get the idea.) It
may also be relevant that the Japanese term doesn't conflate the entire
apparatus with the individual light(s) that are part of it, as the English
term "traffic light" does. (しんごう is really closer to "traffic signal.") In any
case, it is far more usual to say しんごうがあかになりました.

