Learn Hardcore Japanese: kono ryou ni ha gaikoku kara kita ryuugakusei ga takusan sunde imasu. - Many international students from foreign countries live in this dorm.

You could grammatically say この寮に外国から来た留学生がたくさん住んでいます, but it would sound more neutral and less like you’re presenting “this dorm” as the main topic. With には, you’re highlighting “this dorm” as the context you want the listener to focus on.

Why is が used with 留学生 instead of は?

In this sentence:

留学生がたくさん住んでいます。

が marks 留学生 as the grammatical subject: it tells us who is doing the action (住んでいます = “are living”).

If we used 留学生は, it would shift 留学生 to the topic: “As for international students, in this dorm, many live (here)…” That’s a slightly different nuance and would usually require restructuring the sentence.

Here, the main point is:

In this dorm, the people who live here are “international students who came from abroad.”

So この寮には is the topic (where we’re talking about), and 留学生 is the subject (who is living there), so が is appropriate.

Why is 来た (past tense) used in 外国から来た留学生, even though the students are still here?

来た here doesn’t mean “they came (and now it’s over)” in a purely past-time sense. It’s being used to modify 留学生 and describe what kind of students they are:

外国から来た留学生 = “students who came from foreign countries” → “international students.”

This is the same pattern as:

昨日買った本 = “the book (that I) bought yesterday”
ドイツから来た先生 = “the teacher who came from Germany”

The action of “coming” happened in the past, but its result is relevant now: they are in the dorm because they came from abroad. So it’s natural to use the past form 来た as a relative clause modifying 留学生.

What is the difference between 外国から来た留学生 and just 外国人?

外国人 (がいこくじん) = “foreigner, non-Japanese person” (any non-Japanese person).
留学生 (りゅうがくせい) = “international student / exchange student” (specifically someone studying abroad).

So:

外国人 focuses on nationality or origin.
留学生 focuses on being a student studying abroad.

外国から来た留学生 emphasizes both:

They are students.
They came from foreign countries (i.e., they’re international students, not Japanese students).

You wouldn’t usually replace this with 外国人, because then you’d lose the “student” meaning.

What does たくさん do here, and where can it go in the sentence?

たくさん means “many / a lot.”

In this sentence:

留学生がたくさん住んでいます。
Literally: “International students (subject) a lot live.”

This is understood as:

“A lot of international students live (here).”

Other natural positions for たくさん:

たくさんの留学生が住んでいます。
→ “Many international students live (here).”
留学生が住んでいます。たくさんいます。
→ “International students live here. There are many (of them).”

All are grammatical; the nuance is slightly different in focus, but the overall meaning (“there are many”) stays the same.

What exactly does 住んでいます mean, and why not just 住みます?

住んでいます is the 〜ている form of 住む (“to live / reside”).

住む by itself is more like “to take up residence / to start living (somewhere).”
住んでいる describes the resulting state of living somewhere: “is living / lives.”

Using polite form:

住んでいます = “(they) live” / “(they) are living.”

If you said 住みます, it sounds more like:

“(They) will live (there).” / “(They) live (there) (in a generic statement),” but for 住む, native speakers overwhelmingly use 住んでいる to describe current residence.

So:

この寮には〜住んでいます = “In this dorm, (they) live / are living.”
This is the natural way to say someone lives somewhere.

Why is there no explicit subject like 彼らは or その留学生は?

Japanese often omits subjects when they’re clear from context.

Here, 留学生が is actually the subject:

外国から来た留学生がたくさん住んでいます。

There’s no need to add 彼らは (“they”) because it would be redundant. The sentence already tells us clearly:

Who lives there: 外国から来た留学生 (international students who came from abroad)
Where they live: この寮には
That there are many: たくさん

Japanese prefers to keep sentences compact and omit pronouns like “they,” “he,” “she” unless needed for clarity or emphasis.

What does から mean in 外国から, and why is it needed?

から is a particle meaning “from” (starting point).

外国 = “foreign country / foreign countries”
外国から = “from foreign countries”

So:

外国から来た留学生 = “students who came from foreign countries.”

Without から, you’d just have 外国来た留学生, which is ungrammatical. 来る (to come) needs a marker to show the source:

アメリカから来た人 = “person who came from America”
フランスから来た先生 = “teacher who came from France”

Why is この used instead of その or あの before 寮?

この／その／あの all mean “this / that,” but differ in distance and perspective:

この寮 = “this dorm (near me, the speaker, or ‘this dorm we’re in’ / ‘this dorm I belong to’).”
その寮 = “that dorm (near you or already mentioned in the conversation).”
あの寮 = “that dorm (over there, away from both of us, or not closely related to either of us).”

In many real situations, the speaker might currently live in or be associated with the dorm, so この寮 (“this dorm”) is natural.

If the dorm is something only the listener is connected to, その寮 might be more appropriate.

Is the word order fixed? Can I rearrange parts like in English?

Japanese word order is more flexible than English, but there are rules and common patterns.

Basic structure here:

この寮には (location + topic)
外国から来た留学生が (subject)
たくさん (quantity)
住んでいます (verb)

Variations that are still natural:

この寮には外国から来た留学生が住んでいます。たくさんいます。
外国から来た留学生がこの寮にはたくさん住んでいます。

But you must:

Keep particles with the words they belong to (寮には, 留学生が, 外国から, etc.).
Keep the verb 住んでいます at or near the end.

You cannot, for example, split 外国から来た away from 留学生, or move 住んでいます to the middle of the sentence like English.