GRAMMAR DETAIL

〜までになった

to have reached the point where

Indicates reaching, after sustained change or effort, a level that was previously unattainable.

Examples

長年の研究によって、病気の原因を特定できるまでになった。

Years of research have brought us to the point where we can identify the cause of the disease.

彼は一人で海外旅行ができるまでになった。

He has reached the point where he can travel abroad by himself.

練習を重ね、自然に会話できるまでになった。

After repeated practice, they reached the point where they could converse naturally.

Structure: までになった follows an achievable action and emphasizes reaching that level through change or effort.
Basic usage: 練習を重ね、自然に会話できるまでになった。 describes reaching natural conversational ability through repeated practice.

A change in ability versus an attained level
- 会話できるようになった reports becoming able to converse. 会話できるまでになった presents that ability as an endpoint of development, giving greater prominence to the level achieved.
The action and the sentence's tense
- 会話できる describes what is possible at the attained stage, while final なった reports the change of reaching it. The ability level is presented as できるまでになった, rather than changing the earlier verb to できた.