Learn Hardcore Japanese: mado wo simete mo ii desu yo.

In this pattern, も comes from the “even if …” meaning of V‑て + も. Literally, 閉めて(も)いい is “It’s good even if you close (it),” which functions as “It’s allowed/okay to close (it).” In everyday speech, people sometimes drop も (e.g., 閉めていい), but 〜てもいい is the standard textbook form and sounds a bit more neutral/polite.

Why is を used with 窓 instead of が?

Because 閉める is a transitive verb (someone closes something). You mark the direct object with を: 窓を閉める. The intransitive counterpart is 閉まる: 窓が閉まる (“the window closes/gets closed” on its own).

What does the sentence‑ending よ add?

よ adds friendly emphasis and signals you’re informing or reassuring the listener. 閉めてもいいです is neutral; 閉めてもいいですよ feels more like “Go ahead—it’s fine.” It can make the permission sound warmer and more encouraging.

Could I use ね instead of よ? What would change?

よ: giving new info/emphasis to the listener (“It’s okay, you know.”).
ね: seeking agreement/confirmation (“It’s okay to close it, right?”). So 閉めてもいいですね sounds like you think it’s okay and you’re inviting the listener to agree, not simply giving permission.

How polite is this sentence, and how can I adjust the register?

Neutral polite: 閉めてもいいです。
Friendly polite: 閉めてもいいですよ。
More formal: 閉めても構いません(よ)。 / 閉めてもよろしいです(よ)。
Casual: 閉めてもいいよ。 / 閉めていいよ。 Choose based on relationship and situation.

How do I ask for permission to close it myself?

Use 〜てもいいですか:

窓を閉めてもいいですか。 (polite/standard)
窓を閉めていいですか。 (also common, a bit more casual) Very polite: 窓を閉めてもよろしいでしょうか。

What’s the difference between giving permission and making a request?

Giving permission (allowing the other person to do it): 閉めてもいいです(よ)。 (“You may close it.”)
Requesting them to do it: 閉めてください。 / 窓を閉めていただけますか。 (“Please close it.” / “Could you close it, please?”) They serve different social functions.

How do I say “You don’t need to close it” versus “Please don’t close it”?

“You don’t need to (it’s okay even if you don’t)”: 閉めなくてもいいです(よ)。
“Please don’t close it” (polite prohibition): 閉めないでください。 Stronger prohibition: 閉めてはいけません。 / Casual: 閉めちゃダメ。

Why are there spaces between the words here?

Standard Japanese writing doesn’t use spaces. Teachers and textbooks sometimes insert spaces to show word boundaries for learners. In normal text you’d write: 窓を閉めてもいいですよ。

How is 閉めて formed?

閉める is an ichidan (る‑verb). For the て‑form, drop る and add て → 閉めて. So: 閉める → 閉めて.

Is いい the same as よい? Which should I use?

They’re essentially the same word. いい is the common conversational form; よい feels more formal/written. Negatives usually use よくない rather than いくない. In permission patterns, 〜てもいい is most natural; very formal speech may use 〜てもよろしい.

Can I drop です?

Yes, in casual speech: 閉めてもいいよ。 Adding よ keeps the friendly reassurance. With strangers/superiors, keep です/ます.

Can I omit を after 窓?

In casual conversation, the object marker can be dropped when context is clear: 窓、閉めてもいいですよ。 However, in careful or written Japanese, keep を: 窓を閉めてもいいですよ。 You can also topicalize with は for contrast: 窓は閉めてもいいです (“As for the window, it’s okay to close it.”).

How is this read and pronounced naturally?

Reading: まどをしめてもいいですよ。 Romanization: Mado o shimete mo ii desu yo. In natural speech, the u in です is often devoiced, sounding like “des.” いい is a long “ii” vowel.

Does 閉めたらいい mean the same thing as 閉めてもいい?

No. 閉めてもいい = permission (“It’s okay to close it”). 閉めたらいい = suggestion/advice (“You should/It would be good if you closed it”), which can sound more prescriptive.

Is 〜ても大丈夫 the same as 〜てもいい?

They overlap but nuance differs:

〜てもいい = permitted/allowed.
〜ても大丈夫 = “it’s okay/safe,” implying no problem will result. In many contexts both work, but 〜てもいい is the canonical “permission” form.

If I want to offer to close it myself, what should I say?

Use a volitional offer: 私が窓を閉めましょうか。 (“Shall I close the window?”) This is often more considerate than giving the other person permission to do it. You can also say: 窓、閉めましょうか。