# Difference between 書かないようになった and 書かなくなった?

Example sentences:

ぜんぜん長い手紙を書かないようになった。

ぜんぜん長い手紙を書かなくなった。

My Translation: I never write long letters anymore.

I believe they both mean the same thing but there's obviously some difference I don't know about.

• 意味は同じですね。違いは・・・わかりません・・・(上の文の方が、ちょっと回りくどい、とか？) – user1016 Jun 8 '14 at 14:49
• I agree with Choko. Out of curiosity, are these two sentences that you saw or read somewhere? What's the context here? – Ataraxia Jun 8 '14 at 15:10
• The second one was an example sentence in my textbook, the first I wrote myself based on the ようになった grammar point to use as a direct comparison. – Mononoke Jun 8 '14 at 16:19
• (^ 関西弁では「よう」使うけどね・・・ →「書か(へ)んよう(に)なった」とか) – user1016 Jun 9 '14 at 6:45

I think they have the same meaning. The basic difference is that 〜ようになる is commonly used after positive verbs, while 〜くなる is commonly used for negative verbs.

Why? Well, negative verbs are morphologically shaped like adjectives, so they have the shorter 〜くなる form available, and that's what people use 99% of the time. That's not possible with positive verbs, so for those people use 〜ようになる instead—for example, 「見えるようになる」.

To get some numbers to back this up, I searched the Balanced Corpus of Contemporary Written Japanese (BCCWJ) using the freely available 少納言 tool. Here's what I found:

  なくなる　　　　  6527 results
ないようになる　  49 results 

In other words, the short form 〜なくなる is over a hundred times more common!

In contrast, there are 6513 results for ようになる alone. If you search for this phrase, you'll see that the vast majority of the time, it's used after positive verbs.

(Note: To reduce false positives, I typed [^がもは少危]\$ into the 前文脈 ("preceding context") field. This filtered out results like 少なくなる or 〜がなくなる and focused the results on verbs. If you'd like to get the same numbers I did, you'll need to do the same.)