てもいい to ask if someone is allowed to do something

Question

Can the てもいい form be used to ask if someone has the permission to do something?

For example to ask if a women has the permission to smoke here :

彼女はここでタバコを吸ってもいいですか

Answer 1

Short Answer

Yes, no problem.

---

Variances

"Asking" includes several intentions. Verification, validation, confirmation, and so on. Depending on such subtle nuance, you may want to insert an "ん" in your example sentence.

Using the exact same English phrase for all the following scenarios may not be the best choice, but I'll try sticking with "Can/may that woman smoke (cigarettes) here?" for each case. Note that they're all casual conversation - not rude, not formal. Consider the likes of よい or 問題ない when looking for formality.

I'd say 彼女はここでタバコを吸ってもいいですか? for:

Yes or no question

You don't know the rules, don't really care about the general rules, and you just want to ask if that woman is allowed to smoke, before she lights it up - Can/may that woman smoke (cigarettes) here?

---

I'd say 彼女はここでタバコを吸ってもいいんですか？ for:

Wait! Can she?

The next day, you notice that woman is enjoying her smoke near a fire hazard sign. Assuming she's violating the rules, you want to warn her so she don't get in trouble. But before you act, you want to verify your assumption - Can/may that woman smoke (cigarettes) here?

or

What? Can she?

Inspired by her, you start smoking too. One day, you were told that you are not allowed to smoke there. But nobody complains when she smokes. You think it's unfair, and would like to challenge the situation - Can/may that woman smoke (cigarettes) here?

Answer 2

Yes your sentence is correct, but it may be natural to use が here:

彼女がここでタバコを吸ってもいいですか？
Is it okay if she smokes here?

This is because 彼女 belongs to a subordinate clause (ても-clause), where the subject is not topicalized with は.

は is appropriate when a contrastive-は is intended or when "she" needs to be emphasized as the topic of the entire sentence somehow. For example:

彼女はここでタバコを吸ってもいいですか？
(Smoking is basically prohibited here but she may be special, so) can she smoke here?
(Now let's talk about her next,) can she smoke here?

Answer 3

はい、そうです。 あなたが言っているように、この表現は許可を持っているかを聞くときに使います。

他にも、何かをすることは可能か？（英語だとCan I do〜 ）同じ意味です。

Yes, it is.
As you say, this expression is used to ask if you have a permission.

---

例：(Examples:)

• そのお水を飲んでもいいですか？(Can I drink the water?)

• これをもらってもいいですか？(Can I keep this? OR Can I have this?)

• ゲームをしてもいいですか？（Can I play game?)