Learn Hardcore Japanese: koko de ziyuu ni suwatte mo ii desu.

に is usually used for:
- Locations of existence: where something/someone is
  - ここに人がいます。 – There is a person here.
- Destinations: where someone/something goes to
  - ここに座ります。 – I will sit here (as a destination of the action).
で is used for:
- Locations where an action happens (place of action)
  - ここで勉強します。 – I study here.
  - ここで座ってもいいです。 – It’s okay to sit here (this is the place where the action “sitting” happens).

In ここで自由に座ってもいいです, the focus is “the place where you may perform the action (sit),” so で is natural.
If you said ここに座ります, you’re choosing/announcing this spot as your destination to sit down, not giving permission in general.

What does 自由に do here, and why does it have に?

自由 means freedom / free.
自由に is the adverbial form: “freely,” “as you like.”

In Japanese, adding に to some nouns and な-adjectives often makes them adverbs:

静か → 静かに (quiet → quietly)
安全 → 安全に (safe → safely)
自由 → 自由に (free → freely)

So in this sentence:

自由に座る = “to sit freely / to sit as you like”
ここで自由に座ってもいいです。 = “You’re allowed to sit here freely / however you like.”

What is the function of 〜てもいい in 座ってもいい?

The pattern [verb in て-form] + も + いい means:

“It is okay if (you) do …”
“You may / are allowed to do …”
“You can do … (permission)”

So:

座ってもいい
literally: “Even if (you) sit, it’s good/okay.”
more naturally: “You may sit / It’s okay to sit.”

The も here comes from the original meaning “even if,” but in this set phrase 〜てもいい, it’s best to remember it as a standard permission pattern:

見てもいい – You may look.
入ってもいい – You may enter.
座ってもいい – You may sit.

Why is 座って used and not something like 座ります or 座りて?

座って is the て-form of the verb 座る (to sit).

Dictionary form: 座る
ます-form: 座ります
て-form: 座って

The permission pattern 〜てもいい always uses the て-form, never the ます-form:

✔ 座ってもいい
✖ 座りますもいい

So the structure is:

座る → 座って → 座ってもいい → 座ってもいいです (polite).

What is the dictionary form of 座って, and how is it conjugated?

The dictionary form is 座る (to sit).

Basic conjugations:

Dictionary/plain present: 座る – to sit
Polite present: 座ります
Plain past: 座った
Polite past: 座りました
て-form: 座って
Negative plain: 座らない
Negative polite: 座りません

In this sentence we need the て-form because of the pattern 〜てもいい for permission: 座ってもいいです.

Why is there no subject like I or you in this sentence?

Japanese often omits the subject when it’s clear from context.
In English we must say “You may sit here,” but in Japanese:

Context usually makes it obvious that the sentence is giving you permission (the listener).
So just ここで自由に座ってもいいです is natural and complete.

If you really wanted to include an explicit subject, you could say:

あなたはここで自由に座ってもいいです。 – You may sit here freely.
But in everyday Japanese this sounds a bit stiff or overly pointed; it’s usually omitted.

The default interpretation here is:
(You) may sit here freely.

What does です add at the end of 座ってもいいです?

です makes the sentence polite.

座ってもいい。 – You may sit. (plain/casual)
座ってもいいです。 – You may sit. (polite)

So the full sentence:

ここで自由に座ってもいいです。

is polite, suitable for speaking to someone you don’t know well, customers, strangers, etc.

In casual speech among friends, you’d more likely hear:

ここで自由に座ってもいいよ。
or just
ここに座っていいよ。

How would I turn this sentence into a question like “May I sit here freely?” in Japanese?

To make it into a question asking for permission, you add か:

ここで自由に座ってもいいですか。
– May I sit here freely?

Structure:

座ってもいいです。 – You may sit. (statement of permission)
座ってもいいですか。 – May I sit? (requesting permission)

This is a very common pattern:

見てもいいですか。 – May I look?
入ってもいいですか。 – May I come in?
使ってもいいですか。 – May I use it?

Can I change the word order, like 自由にここで座ってもいいです? Is that still correct?

Yes, Japanese word order is relatively flexible with modifiers like ここで and 自由に.

All of these are grammatically okay, with slight differences in emphasis:

ここで自由に座ってもいいです。 – At this place, you may sit freely.
自由にここで座ってもいいです。 – Freely, here, you may sit. (a bit unusual, but understandable)
ここで座っても自由にいいです。 – feels unnatural; 自由に normally directly modifies the verb 座る, so it should be near 座って.

The most natural and typical is the original:

ここで自由に座ってもいいです。

because:

ここで (place)
自由に (manner)
座ってもいいです (main predicate)

Flowing from more setting information → main action is very standard.

What nuance does 自由に add compared to just ここで座ってもいいです?

Compare:

ここで座ってもいいです。 – You may sit here.
ここで自由に座ってもいいです。 – You may sit here freely / however you like.

自由に suggests:

No strict rules about where exactly or how you sit.
You can choose your seat or posture more freely.
It softens the sentence, making it sound a bit more inviting or generous.

Without 自由に, it’s simple permission: “It’s okay to sit here.”
With 自由に, it’s more like: “Feel free to sit here.”