Learn Hardcore Japanese: ryuugakusei no tomodati to issyo ni nihongo de kaiwasuruno ha tanosii desu. - It’s fun to have conversations in Japanese with my international student friends.

“a friend who is an exchange student” (friend = exchange student)
“a friend of an exchange student” (friend belongs to or is associated with an exchange student)

In real usage, the most natural, default reading of 留学生の友達 is usually:

“a friend who is an exchange student”

If the speaker wanted to clearly say “a friend of an exchange student,” they would usually add more context or say something like:

留学生の友達の日本人 – the Japanese friend of an exchange student

So for this sentence, you can safely read 留学生の友達 as “a friend who is an exchange student” (i.e., “my exchange-student friend”).

Why do we have both と and 一緒に? Don’t they both mean “with”? Isn’t one of them enough?

You often see と and 一緒に together, but they are doing slightly different things.

A と = “with A” (marks the person you’re together with, or doing something with)
一緒に = “together” / “together with”

So in:

留学生の友達と一緒に

You can think of it as:

“together (一緒に) with (と) my exchange-student friend”

Is one of them enough?

留学生の友達と日本語で会話するのは楽しいです。
– Grammatically OK, and still naturally understood as “(talk) with my exchange-student friend.”
留学生の友達と一緒に日本語で会話するのは楽しいです。
– Adds explicit nuance of “together with my friend,” slightly emphasizing the feeling of doing it together.

So と is required to mark the companion; 一緒に is optional and adds the nuance “together.”

What does 一緒に mean exactly, and why is there a に after 一緒?

一緒 (いっしょ) by itself is a noun meaning “together” or “the same (place/time/etc.)”.

Adding に turns it into an adverbial form:

一緒に = “together” (adverb describing how you do the action)

In Japanese, nouns often take particles to function as adverbs. 一緒に is a very common fixed expression:

一緒に行きましょう。 – Let’s go together.
友達と一緒に勉強します。 – I study together with my friend.

一緒で would usually mean something like “in the same (condition/state)” and is used differently (e.g., このシャツは色が一緒です – “These shirts are the same color”), so 一緒で is not correct here.

Why is it 日本語で会話する and not 日本語を会話する? What does で mean here?

The particle で has several uses; one of them is to show the means or method by which an action is done.

日本語で = “by means of Japanese” / “in Japanese (language)”

So:

日本語で会話する = “to have a conversation in Japanese”

You do not say 日本語を会話する, because 会話する (to converse, to have a conversation) is not a simple “verb that takes a direct object of language.”
Instead, the language is treated as the means, not the object.

Compare:

日本語を勉強する – study Japanese (Japanese is the direct object of “study”)
日本語で話す – speak in Japanese (Japanese is the medium/method of speaking)

So で is correct here to show the language used for the conversation.

What is the difference between 会話する and more common verbs like 話す or しゃべる?

All three are related to speaking, but they differ in nuance:

話す (はなす)
- Very common, general “to speak / to talk / to tell.”
- Can be formal or casual, very flexible.
しゃべる
- More casual, often “to chat / to talk a lot / to gab.”
- Slightly colloquial feel.
会話する (かいわする)
- Literally “to do conversation,” i.e., to have a conversation.
- Sounds a bit more formal or textbook-like.
- Emphasizes exchange between people rather than just producing speech.

In this sentence, 日本語で会話するのは楽しいです, 会話する focuses on the interactive conversation aspect, which fits well with “It’s fun to have conversations in Japanese (with my friend).”

You could also say:

日本語で話すのは楽しいです。 – “Speaking in Japanese is fun.” (slightly more general)

What is 会話するの doing here? Why is there a の after the verb?

The の here is a nominalizer – it turns the verb phrase into a noun-like phrase.

会話する = (to) have a conversation
会話するの = the act of having a conversation / having a conversation

Japanese often uses の (or sometimes こと) to turn an action into “a thing” so that it can take particles like は, が, を, etc.

So:

会話するのは楽しいです。
= “(As for) having conversations, (it) is fun.”

In English, we might use “having conversations” or “to have conversations” as the subject. In Japanese, adding の makes that possible.

Why is there a は after 会話するの? Why not が or を?

Here, 会話するの is being set as the topic of the sentence, and は is the topic marker.

会話するのは楽しいです。
= “As for having conversations, (it) is fun.”

If you used が, the nuance would be different:

会話するのが楽しいです。
= “What is fun is having conversations.”

Both are grammatically correct and both are common. The difference is subtle:

A は B – “As for A, (it) is B.” (topic, sometimes contrastive)
A が B – “A is B.” (subject-focused, often answering “what/who is B?”)

In many contexts, both are acceptable, but のは and のが carry slightly different emphasis. With のは, you’re more clearly framing the whole phrase “having conversations in Japanese with my exchange-student friend” as the topic.

Why is it 楽しいです and not 楽しいだ? Don’t we usually use だ with nouns and adjectives?

楽しい is an い-adjective. The rules are:

Plain form: 楽しい
Polite form: 楽しいです

You do not normally say 楽しいだ in standard Japanese.

For い-adjectives:

You add です directly to make it polite.
- 高い → 高いです
- 寒い → 寒いです
- 楽しい → 楽しいです

For nouns and な-adjectives, you use だ / です as the copula:

学生だ / 学生です – is a student
便利だ / 便利です – is convenient

So here, 楽しいです is the correct polite form.

How flexible is the word order in this sentence? Can I move things around like in English?

Japanese word order is relatively flexible, but the verb usually comes at the end.

Your sentence is:

留学生の友達と一緒に日本語で会話するのは楽しいです。

You can reorder many of the chunks before the verb/topic, for example:

日本語で留学生の友達と一緒に会話するのは楽しいです。
留学生の友達と一緒に会話するのは日本語で楽しいです。 (this one sounds a bit odd; it seems to say “it’s fun in Japanese” specifically)

The most natural is generally to keep the chunks close to the verb they modify, and to keep the verb (or verb+のは) near the end:

Companion: 留学生の友達と一緒に
Method/language: 日本語で
Action: 会話する (＋のは)
Predicate: 楽しいです

Major rule to remember:
The finite verb (or verb + の/こと) comes at or very near the end.
Within that, you have some freedom, but Japanese does not freely move the predicate around like English.

Is 一緒に necessary here? Can I just say 留学生の友達と日本語で会話するのは楽しいです?

Yes, 一緒に is not strictly necessary.

留学生の友達と日本語で会話するのは楽しいです。
– Perfectly natural. It already implies you are conversing with your friend.

Adding 一緒に:

留学生の友達と一緒に日本語で会話するのは楽しいです。

This version slightly emphasizes the “togetherness” feeling – “together with my exchange-student friend, having conversations in Japanese is fun.”

So:

Without 一緒に: neutral “with my friend”
With 一緒に: more explicit “together with my friend,” a bit warmer/clearer about doing it together

Why does Japanese use で to talk about language (as in 日本語で)? In English we usually say “in Japanese.”

In English, we say:

“talk in Japanese,” “write in English.”

In Japanese, that same idea is typically expressed with で, which marks:

means, method, or medium of the action.

So:

日本語で話す – speak by means of Japanese → speak in Japanese
英語で書く – write in English
フランス語で考える – think in French

You can think of it as:

X で = “using X” / “by means of X”

The “medium of communication” is treated like a tool or method, which is why で is used rather than something like に or を.

Can this sentence be shortened in casual conversation? What might a more casual version look like?

Yes, Japanese often drops parts when they’re obvious from context, especially in casual speech.

Original polite version:

留学生の友達と一緒に日本語で会話するのは楽しいです。

Possible casual versions:

留学生の友達と一緒に日本語で会話するのは楽しい。
– Just drop です. Still complete, but casual.
留学生の友達と一緒に日本語で会話するの楽しい。
– Drop は after の (common in speech).
More natural, slightly simplified vocabulary:
留学生の友達と一緒に日本語で話すの楽しい。
– Uses 話す instead of 会話する, which sounds more everyday.

If context is clear, you could even omit parts like 留学生の, 一緒に, etc., but that depends on what has already been mentioned.