asita tomodati to issyo ni eiga wo mi ni ikimasu.

Japanese word order is much more flexible than English, but the basic pattern is that the verb comes at the end.

A natural way to break this sentence down is:

• 明日 = tomorrow
• 友達と一緒に = together with a friend / with my friend
• 映画を = a movie
• 見に行きます = will go to watch

So Japanese often builds the sentence by giving the time, then other information, and then putting the main action at the end.

A very literal structure would be:

• Tomorrow / with a friend / a movie / to watch / will go

That sounds strange in English, but it is normal in Japanese.

Here, と means with when used after a person or animal.

• 友達と = with a friend
• 母と = with my mother
• 先生と = with the teacher

So in this sentence:

• 友達と一緒に = together with a friend

Note that と can also mean and in other contexts, but here it clearly means with.

Yes, they are related, so learners often wonder if this is repetitive.

• 友達と already means with a friend
• 一緒に means together

So 友達と一緒に is like saying:

• together with a friend
• with a friend, together

This is very natural in Japanese and adds a sense of doing the activity together.

You can sometimes say just:

• 友達と映画を見に行きます。

That still means I’m going to see a movie with a friend.

Adding 一緒に makes the idea of being together a little more explicit.

一緒 means together or the same company/group.
When used adverbially to describe how an action is done, it often appears as 一緒に.

So:

• 一緒に行きます = go together
• 一緒に食べます = eat together

The に here helps turn 一緒 into something like together in English, modifying the verb.

In this sentence:

• 友達と一緒に = together with a friend

Time words like 明日, 今日, and 昨日 often do not need a particle.

So these are normal:

• 明日行きます。 = I’ll go tomorrow.
• 今日勉強します。 = I’ll study today.

You may sometimes see に with time expressions, but with words like 明日, it is usually omitted.

So:

• 明日友達と一緒に映画を見に行きます。
  is completely natural.

を marks the direct object of the verb.

Here, the thing being watched is:

• 映画 = movie

So:

• 映画を見ます = watch a movie

Even though the full sentence has 見に行きます, the object of 見る is still 映画, so it takes を.

This is a very common question.

In Japanese, when you say go somewhere to do something, you use the verb stem + に行く.

For 見る:

• dictionary form: 見る
• stem: 見

So:

• 見に行きます = go to watch

Not:

• 見ますに行きます ❌

Other examples:

• 食べに行きます = go to eat
• 買いに行きます = go to buy
• 会いに行きます = go to meet

So the pattern is:

• verb stem + に + 行く

The pattern is:

• [verb stem] + に行く = go in order to do something

In your sentence:

• 見 = stem of 見る
• に = marks purpose
• 行きます = go

So:

• 映画を見に行きます = go to watch a movie

This に is different from the に in 一緒に.
Here, it shows the purpose of going.

行きます is the polite non-past form of 行く.

• 行く = plain form
• 行きます = polite form

Japanese uses different speech styles depending on the situation. The ます-form is common in:

• class
• speaking to strangers
• polite conversation
• textbook example sentences

So this sentence is polite and natural for beginner study.

The plain version would be:

• 明日友達と一緒に映画を見に行く。

Japanese does not have a separate future tense the way English does. The non-past form can mean:

• present
• habitual
• future

In this sentence, 明日 makes the time clear, so 行きます is understood as future:

• I will go

So the sentence means something like:

• Tomorrow, I will go see a movie with a friend.

Japanese often omits the subject when it is obvious from context.

In English, you usually need to say I, he, she, etc.
In Japanese, if the speaker is talking about their own plans, the subject is often simply left out.

So this sentence naturally implies:

• I am going tomorrow with a friend to watch a movie.

If needed, you could say:

• 私は明日友達と一緒に映画を見に行きます。

But very often 私は is unnecessary.

By itself, 友達 can mean:

• a friend
• friends

Japanese nouns usually do not change form for singular vs. plural the way English nouns do.

So 友達と一緒に could mean:

• with a friend
• with friends

The exact meaning depends on context. In many textbook translations, it is rendered as with a friend, but with friends is also possible unless the context says otherwise.

Yes, to some extent. Because the particles show each word’s role, Japanese word order has some flexibility.

For example, these are also possible:

• 友達と一緒に明日映画を見に行きます。
• 明日映画を友達と一緒に見に行きます。

They all mean roughly the same thing.

However, some orders sound more natural than others depending on emphasis.
The original sentence is a very normal, easy-to-understand order.

Yes, that is grammatically possible, and a native speaker would understand it. But it may sound a little less natural depending on context.

A more common order is:

• 明日友達と一緒に映画を見に行きます。

This keeps 見に行きます together as one action unit near the end, which is very natural.

So your version is not wrong, but the original order is smoother for most neutral situations.

There are two verbs involved:

• 見 comes from 見る = to see / to watch
• 行きます comes from 行く = to go

Because this sentence uses the purpose pattern verb stem + に行く, 見る changes to its stem 見.

So the underlying idea is:

• 映画を見る
• 行く

Combined:

• 映画を見に行く = go to watch a movie