53326
> 寝ていい？

I've learned that to ask permission for doing something, you needed to use
～てもいい but the more I read japanese, the more I come across ～ていい. What is the
difference ? Is the latter a colloquial version of ～てもいい ?
CC BY-SA 3.0
2017-09-16T17:11:56.540
53288
2017-09-18T07:20:22.377
20501
question
grammar
Difference between てもいい and ていい?
As I know, verb with te-form + もいい often used to asking permission about what
you want to do (i.e. sleeping in your question as indicated by 寝る => 寝て in te-
form). Before advancing to the usage, there are basic patterns when asking for
permission to someone else:

> 1) te-form verb + もいい (casual)
>
> 2) te-form verb + もいいですか (polite)
>
> 3) te-form verb + もいいでしょうか (more polite)
>
> 4) te-form verb + もかまいませんか (also more polite)
>
> 5) te-form verb + もよろしいでしょうか (very polite)

In more casual conversation the "も" usually omitted, it shortened to "ていい"
instead.

So that 寝ていい is a shortened form of 寝てもいい (can I sleep?) in casual situations,
as given by [examples](http://www.guidetojapanese.org/haveto.html):

> In casual speech, 「～てもいい」 sometimes get shortened to just 「～ていい」.
>
> （１） もう帰っていい？- Can I go home already? (from もう帰ってもいいですか。)
>
> （２） これ、ちょっと見ていい？- Can I take a quick look at this? (from これ、ちょっと見てもいいですか。)

Note that なく is used before ても to form negative context (can/will it be good
if don't...). If the verb ends with "む" like 読む or 進む (which changes to ～んで),
the ～でもいい form used instead of ～てもいい.
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2017-09-18T01:16:48.943
53319
2017-09-18T01:16:48.943
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53288
answer
There is a difference even though it might be fairly subtle. **_The difference
is one of nuance and probability; It has little to nothing to do with
formality/colloquiality_**.

> 「Verb in Te-Form + いい？」

The speaker would tend to possess a firm desire to perform the action and he
is seeking permission to do so.

Upon receiving the permission, therefore, there is a high chance that he would
actually take the action.

> 「Verb in Te-Form + **も** + いい？」

The speaker is surely considering taking the action for which he is seeking
permission, but his desire to actually perform the said action would often
tend to be less firm than that of the person who does **_not_** use the 「も」.

Upon receiving the permission, there is a good chance that this person
(speaker) might actually opt to take a completely different action.

For this reason, adding a 「も」 makes both the question and the questioner sound
less pushy or self-assertive.
CC BY-SA 3.0
2017-09-18T07:20:22.377
53326
2017-09-18T07:20:22.377
53288
answer