Look at these two sentences:
A. 音楽を聞かなくなった。 → I stopped listening to music. B. 音楽を聞かないようになった。 → I stopped listening to music.
The English translations look the same, but the Japanese meanings differ: A means you stopped suddenly, while B means you stopped gradually.
なくなった — Stopped Suddenly
Verb negative form (ない-form) + なくなる = suddenly stopped doing something.
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音楽を聞かなくなった。 → I stopped listening to music. (Someone told me listening to music at night is bad for my health, so I stopped from that point on.)
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甘いものを食べなくなった。 → I stopped eating sweets. (The doctor said one thing, and I quit immediately.)
なくなった = There is a clear point in time, and from that point on, you stopped doing it.
ないようになった — Gradually Stopped
Verb negative form (ない-form) + ようになる = gradually stopped doing something — there was a process.
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音楽を聞かないようになった。 → I stopped listening to music. (Work got busier and busier, and I gradually stopped listening.)
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甘いものを食べないようになった。 → I stopped eating sweets. (I cut back little by little until I eventually stopped altogether.)
ないようになった = There was a gradual process; it slowly turned into not doing it.
ようになる — Affirmative: Gradually Became Able
The affirmative version of ようになる is even more common — it expresses "gradually became able to do something."
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日本語が話せるようになった。 → I became able to speak Japanese. (After studying for three months, I gradually could speak.)
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朝早く起きられるようになった。 → I became able to wake up early. (I gradually built the habit.)
ようになる = A gradual change in ability or habit.
Comparison Summary
| Expression | Type of Change | Example |
|---|---|---|
| なくなった | Sudden stop | 聞かなくなった |
| ないようになった | Gradual stop | 聞かないようになった |
| ようになった | Gradually started / became able | 話せるようになった |
Self-Test
Q1. After coming to Japan, you got busier every day and gradually stopped listening to music. Which one do you use?
A. 聞かなくなった B. 聞かないようになった
Show answer
B. 聞かないようになった. Getting busier every day is a gradual process, so you slowly stopped listening = ないようになった.
Q2. After studying Japanese for three months, you gradually became able to speak. How do you say this?
Show answer
日本語が話せるようになった。 A gradual change in ability = ようになった.
Summary
- なくなった = Suddenly stopped (a specific point in time)
- ないようになった = Gradually stopped (a process)
- ようになった = Gradually became able to / started doing
- Key distinction: whether or not there was a gradual process