Difference between 必死で走る and 必死に走る


I understand that in these expressions the に isn't a particle (I think it
indicates the adverbial form of a na-adjective) but I'm not sure what で is:

> 必死 **に** 走る  
>  [_run like
> crazy_](http://ejje.weblio.jp/content/%E5%BF%85%E6%AD%BB%E3%81%AB%E8%B5%B0%E3%82%8B)  
>  必死 **で** 走る  
>  [_run like
> hell_](http://ejje.weblio.jp/content/%E5%BF%85%E6%AD%BB%E3%81%A7%E8%B5%B0%E3%82%8B)

According to [this answer](https://japanese.stackexchange.com/a/12713/19206)
it's ungrammatical to use で to make na-adjective adverbial. Still, the English
translation is almost the same but the one with で is stronger.




「必死で走る」「必死に走る」 both sound perfectly fine to me, and I believe these are both
grammatically correct.

* * *

> I understand that in these expressions the に isn't a particle (I think it
> indicates the adverbial form of a na-adjective)

I think you're right. According to 明鏡国語辞典, 「必死」 is a 形容動詞/na-adjective, so it
conjugates to its 連用形/continuative form 「必死に」 to modify the 用言/conjugatable
word 「走る」.

* * *

> but I'm not sure what で is... it's ungrammatical to use で to make na-
> adjective adverbial.

In 明鏡, 「必死」 is also categorized as a noun. So the で here is a case
particle/格助詞, and is used in the sense of:

> で 〘格助詞〙  
>  ❹ 動作を行うときの **様態** を表す。「急ぎ足 **で** 歩く」...「笑顔 **で** 答える」「土足 **で** 上がる」  
>  （明鏡国語辞典）

* * *

> the English translation is almost the same but the one with で is stronger.

「必死に～」「必死で～」 don't really sound different to me... I wouldn't find it wrong if
the _crazy_ and _hell_ were swapped :D




「必死で走る」「必死に走る」 both sound perfectly fine to me, and I believe these are both
grammatically correct.

* * *

> I understand that in these expressions the に isn't a particle (I think it
> indicates the adverbial form of a na-adjective)

I think you're right. According to 明鏡国語辞典, 「必死」 is a 形容動詞/na-adjective, so it
conjugates to its 連用形/continuative form 「必死に」 to modify the 用言/conjugatable
word 「走る」.

* * *

> but I'm not sure what で is... it's ungrammatical to use で to make na-
> adjective adverbial.

In 明鏡, 「必死」 is also categorized as a noun. So the で here is a case
particle/格助詞, and is used in the sense of:

> で 〘格助詞〙  
>  ❹ 動作を行うときの **様態** を表す。「急ぎ足 **で** 歩く」...「笑顔 **で** 答える」「土足 **で** 上がる」  
>  （明鏡国語辞典）

* * *

> the English translation is almost the same but the one with で is stronger.

「必死に～」「必死で～」 don't really sound different to me... I wouldn't find it wrong if
the _crazy_ and _hell_ were swapped :D

