Why is the も particle used when asking to borrow something?


If I ask, "Can I borrow a pencil?" I might say: エンピツを借りてもいいですか？

Why do we use the も particle here, since we're not saying **also** this or
that? To express **also** is the main usage of mo I'm familiar with.




Of course, 〜てもいい is not limited to borrowing, but rather any form of
permission.

Being very literal...

> エンピツを借りる "to borrow a pencil"  
>  エンピツを借りていい？ "Is it okay if I borrow a pencil?"  
>  エンピツを借りて **も** いい？ "Is it okay **even** if I borrow a pencil?"

It is certainly not ungrammatical to have a も there (syntactically, you can
insert any 係助詞{かかりじょし} between the て and the following verb/adjective), and
semantically it makes sense as well.

The fact that the form with the も is more _popular_ , however, is just
idiomatic.




Of course, 〜てもいい is not limited to borrowing, but rather any form of
permission.

Being very literal...

> エンピツを借りる "to borrow a pencil"  
>  エンピツを借りていい？ "Is it okay if I borrow a pencil?"  
>  エンピツを借りて **も** いい？ "Is it okay **even** if I borrow a pencil?"

It is certainly not ungrammatical to have a も there (syntactically, you can
insert any 係助詞{かかりじょし} between the て and the following verb/adjective), and
semantically it makes sense as well.

The fact that the form with the も is more _popular_ , however, is just
idiomatic.

