Trying to figure out the Japanese tale's sentence


> ある年のこと、大雨が切れめなく、ザアザアふったので、村は水びたしになってしまい、村人は、 とてもこまりました。

I don't understand the second part "村は水びたしになってしまい". I figured out that this
means "The village ended up becoming dipped in water." But some
transformations I don't get. For example, how and why the verb ひたす became びたし,
which form I didn't manage to find in the internet at all. Also subsidiary
verb しまう(which follows the TE-form of なる, and adds the nuance of "end up",
"unfortunately") somehow became しまい.




> how and why the verb ひたす became びたし

The ひ → び sound change is [連濁]{れんだく}.

みず + ひたし → みず **び** たし (水浸し)  
あさ + かお → あさ **が** お (朝顔)  
ひら + かな → ひら **が** な (平仮名)  
さん + ひき → さん **び** き (３匹)

For more on 連濁, see:

  * [Why does this unvoiced ほ sound become a voiced ぼ sound?](https://japanese.stackexchange.com/q/44775/9831)
  * [What is the difference between tori vs. dori?](https://japanese.stackexchange.com/q/816/9831)

* * *

びた **し** (or ひた **し** ) is the noun form of the verb [浸]{ひた} **す**. It's
originally the continuative form (連用形) of the verb. For more on the noun form
of verbs, see:

  * [Conjunctive form (e.g. 書き) vs Conj + mono (e.g. 書き物)](https://japanese.stackexchange.com/q/32299/9831)
  * [入り and 付き in these sentences](https://japanese.stackexchange.com/q/40835/9831)

* * *

> The subsidiary verb しまう [...] somehow became しまい.

The しまい is the continuative form (連用形) of しまう. This form can be used as a
conjunction. 「水浸しになってしま **って** 、村人はこまりました。」 means the same thing as 「水浸しになってしま
**い** 、村人はこまりました。」 The latter sounds a bit more literary.

This form is called [中止形]{ちゅうしけい} and this usage, [中止法]{ちゅうしほう}. See:

  * [Is there a term for using conjugating verbs such that the sentence continues with another clause?](https://japanese.stackexchange.com/q/9771/9831)
  * [Use of く-form over くて in an い-adjective](https://japanese.stackexchange.com/q/12642/9831)




> how and why the verb ひたす became びたし

The ひ → び sound change is [連濁]{れんだく}.

みず + ひたし → みず **び** たし (水浸し)  
あさ + かお → あさ **が** お (朝顔)  
ひら + かな → ひら **が** な (平仮名)  
さん + ひき → さん **び** き (３匹)

For more on 連濁, see:

  * [Why does this unvoiced ほ sound become a voiced ぼ sound?](https://japanese.stackexchange.com/q/44775/9831)
  * [What is the difference between tori vs. dori?](https://japanese.stackexchange.com/q/816/9831)

* * *

びた **し** (or ひた **し** ) is the noun form of the verb [浸]{ひた} **す**. It's
originally the continuative form (連用形) of the verb. For more on the noun form
of verbs, see:

  * [Conjunctive form (e.g. 書き) vs Conj + mono (e.g. 書き物)](https://japanese.stackexchange.com/q/32299/9831)
  * [入り and 付き in these sentences](https://japanese.stackexchange.com/q/40835/9831)

* * *

> The subsidiary verb しまう [...] somehow became しまい.

The しまい is the continuative form (連用形) of しまう. This form can be used as a
conjunction. 「水浸しになってしま **って** 、村人はこまりました。」 means the same thing as 「水浸しになってしま
**い** 、村人はこまりました。」 The latter sounds a bit more literary.

This form is called [中止形]{ちゅうしけい} and this usage, [中止法]{ちゅうしほう}. See:

  * [Is there a term for using conjugating verbs such that the sentence continues with another clause?](https://japanese.stackexchange.com/q/9771/9831)
  * [Use of く-form over くて in an い-adjective](https://japanese.stackexchange.com/q/12642/9831)

