verb versus noun + する


In the book I'm reading I keep seeing constructs where I would expect a verb
but get the noun form + する. Here's an example:

> 鬼は、大笑いして、「小さな小僧、お前から食べてやろう。」と言いました。  
>  The ogre laughed loudly and said "I will eat you first little boy".

Why is it 大笑いして rather than 大笑って?

Here's another one:

> 私があなたをお守りします。  
>  I will protect you.

Now I'm assuming the お here is honorific (he's talking to a princess). Why is
it 守りします and not 守ります?

Thanks




The two examples have different reasons.

* * *

The prefix **大{おお} always attaches to a noun** , e.g. see 大辞林

> **おお 【大】**
>
> **一** [...]
>
> **二** (接頭)  
>  名詞に付く。
>
>   1. [...]
>
>   2. 程度のはなはだしいことを表す。「—あわて」「—にぎわい」「—騒ぎ」
>
>   3. [...]
>
>

* * *

In the second example お守りします you correctly identified that お is honorific. The
only thing that's missing is the observation that the **honorific お also only
attaches to nouns** , so ~~お守ります~~ wouldn't work. This construction お+[masu-
stem]+する is very common and also lends itself to raising the level of
politeness by replacing する with (the proper conjugation of) 致す{いたす}.




The two examples have different reasons.

* * *

The prefix **大{おお} always attaches to a noun** , e.g. see 大辞林

> **おお 【大】**
>
> **一** [...]
>
> **二** (接頭)  
>  名詞に付く。
>
>   1. [...]
>
>   2. 程度のはなはだしいことを表す。「—あわて」「—にぎわい」「—騒ぎ」
>
>   3. [...]
>
>

* * *

In the second example お守りします you correctly identified that お is honorific. The
only thing that's missing is the observation that the **honorific お also only
attaches to nouns** , so ~~お守ります~~ wouldn't work. This construction お+[masu-
stem]+する is very common and also lends itself to raising the level of
politeness by replacing する with (the proper conjugation of) 致す{いたす}.

