Learn Hardcore Japanese: watasi ha maisyuu tosyokan de nihongo wo benkyousimasu. - I study Japanese at the library every week.

私は毎週図書館で日本語を勉強します。
“As for me, I study Japanese at the library every week.” (neutral statement about yourself)
私が毎週図書館で日本語を勉強します。
“I am the one who studies Japanese at the library every week.” (emphasis/contrast; less common in isolation)

Why doesn’t 毎週 have a particle like に after it?

Time expressions like 毎週 (every week), 毎日 (every day), 昨日 (yesterday), 明日 (tomorrow) are often used without a particle when they just indicate when something happens.

So 毎週図書館で日本語を勉強します is perfectly normal Japanese.

You can sometimes see 毎週に, but that usually adds a different nuance (like “in each week / per week”) and is not needed for simple “every week”. For basic “I do X every week”, you normally just say:

毎週〜します
毎日〜します
週末に〜します ← here に is common because 週末 is more like a specific time point (“on the weekend”)

What exactly does the particle で after 図書館 mean? Why not に?

で marks the location where an action takes place.

Here, 図書館で = “at the library” (the place where the studying happens).

に is used mainly for:

Destination / goal of movement
- 図書館に行きます。 = “I go to the library.”
Location of existence (with verbs like ある / いる)
- 図書館に学生がいます。 = “There are students in the library.”
Specific time point
- ３時に勉強します。 = “I study at 3 o’clock.”

Since 勉強します is an action that happens in a place, 図書館で is correct.

Why is 日本語 marked with を? In English, “Japanese” doesn’t look like a typical direct object here.

In Japanese, を marks the direct object of the verb — what the action directly affects.

With 勉強する (to study), the thing you study is treated as a direct object, so:

日本語を勉強します。 = “(I) study Japanese.”
歴史を勉強します。 = “(I) study history.”
数学を勉強します。 = “(I) study math.”

Even if in English it might feel like “I study Japanese” (no preposition), or for other verbs like “I look at the sky”, Japanese grammar still uses を to mark that direct object:

空を見ます。 = “I look at the sky.” (lit. “I see the sky.”)

Can I change the word order, like 私は日本語を毎週図書館で勉強します? Does the order matter?

Japanese word order is relatively flexible as long as the particles stay attached to the right words. The essential requirement is that the verb usually comes at the end.

All of the following are grammatical and mean basically the same thing, with slight shifts in emphasis:

私は毎週図書館で日本語を勉強します。
私は図書館で毎週日本語を勉強します。
私は日本語を毎週図書館で勉強します。

In normal speech, time (毎週) often comes near the beginning, and place (図書館で) often comes before the object, but there is no strict rule like in English. Changing order can slightly highlight different parts, but the meaning remains clear because of the particles は / で / を.

Why is the verb 勉強します and not 勉強する?

勉強します is the polite form of the verb 勉強する.

勉強する = dictionary/plain form (“to study”)
勉強します = polite -ます form (“study / will study” in a polite way)

Use -ます forms in most conversations with:

teachers
people you don’t know well
at work
any situation where you want to sound polite

With close friends or family, or in casual writing, people use the plain form:

私は毎週図書館で日本語を勉強する。 (casual)

Is 勉強します one word, or is it 勉強 + します (like “do study”)?

Grammatically, it’s 勉強する (to study), and します is the polite form of する (“to do”). So structurally:

勉強 (a noun meaning “study”)
- する (“to do”) → 勉強する (“to study”)
polite form → 勉強します

Verbs like 勉強する, 運動する (to exercise), 練習する (to practice) are often called する-verbs: a noun + する combination that functions as a single verb.

In practice, you can just remember 勉強します as “(I) study” in a polite form.

Why is the English translation “I study Japanese every week at the library” even though the Japanese verb looks like present/future tense? How is tense working here?

Japanese has a non-past form (like 勉強する / 勉強します) that covers both:

present/habitual actions
future actions

So 勉強します can mean:

“I study (regularly).”
“I will study.”

Context decides the exact nuance. With a frequency word like 毎週, the sentence naturally reads as a habitual action:

私は毎週図書館で日本語を勉強します。
= “I study Japanese at the library every week.” (habit)

If you wanted to focus on something happening right now, you might use the progressive:

私は今、図書館で日本語を勉強しています。
= “I am studying Japanese at the library (right now).”

Can I drop 私 and just say 毎週図書館で日本語を勉強します?

Yes. In fact, that’s very common and often more natural. Japanese frequently omits the subject when it’s clear from context.

If you’re talking about your own schedule, just saying:

毎週図書館で日本語を勉強します。

will normally be understood as “I study Japanese at the library every week.”

You would only keep 私は if:

you’re introducing yourself for the first time
you want to contrast with someone else (e.g., “As for me, I study at the library, but my friend studies at home”)

Could I say 図書館で毎週日本語を勉強します without 私 and still be correct?

Yes. That’s also natural. It’s just a different word order:

図書館で毎週日本語を勉強します。
“(I) study Japanese at the library every week.”

This starts with 図書館で, slightly highlighting the location first. Again, subject (I) is understood from context and omitted.

How polite or formal is 勉強します? Is this sentence okay with friends?

勉強します is polite but not overly formal. Using the -ます form is the default polite style in:

classrooms
with teachers
with coworkers
with people you don’t know well

With close friends, many people would switch to the plain form:

毎週図書館で日本語を勉強する。 (casual)

But using 勉強します with friends is not “wrong”; it just makes you sound more formal or distant. As a learner, it’s safe to default to -ます until you’re comfortable with casual speech.

How can I make similar sentences with other time words, like “every day” or “every month”?

You can replace 毎週 with other 毎〜 expressions:

毎日図書館で日本語を勉強します。
“I study Japanese at the library every day.”
毎月図書館で日本語を勉強します。
“I study Japanese at the library every month.”
毎朝家で日本語を勉強します。
“I study Japanese at home every morning.”

The pattern is the same:

(私は) + time word + place + で + object + を + verb(ます)

Particles and structure stay the same; you just swap in different nouns.