Learn Hardcore Japanese: itiniti ni dorekurai nihongo wo benkyousimasu ka?

一日にどれくらい日本語を勉強しますか。
Literally: “In one day, how much do you study Japanese?”
Natural English: “How much do you study Japanese per day?” / “How long do you study Japanese each day?”

This use of に is common with time or frequency expressions:

一日に一回 – once per day
一週間に三回 – three times a week
一時間に１０キロ走ります – I run 10 km per hour

So here に is closest to “per” or “in (the span of)” in English.

Can I drop に and say 一日どれくらい日本語を勉強しますか instead?

Yes, you can. Both are natural:

一日にどれくらい日本語を勉強しますか。
一日どれくらい日本語を勉強しますか。

The difference is minor:

With に: a bit clearer that you mean “per day” as a unit.
Without に: sounds like “In a day, about how much do you study Japanese?” but is usually understood as per day anyway.

In everyday speech, you will hear both. For a learner, it’s perfectly fine to use either; including に is a bit more textbook‑clear.

What does 一日 mean here, and how do you pronounce it: いちにち or ついたち?

In this sentence, 一日 is pronounced いちにち and means “one day / a day (as a unit of time)”.

Japanese has two common readings for 一日:

ついたち – “the first (day) of the month”
- Example: 一日は休みです。 – “I’m off on the 1st.”
いちにち – “one day / all day / a whole day”
- Example: 一日勉強しました。 – “I studied all day.” / “I studied for one day.”

In 一日にどれくらい日本語を勉強しますか, it is clearly the いちにち reading, because we’re talking about a time span (“per day”), not a date on a calendar.

Why is there no subject like “you” or “I” in the sentence?

Japanese often omits the subject when it’s obvious from context.

English needs: “How long do you study Japanese per day?”
Japanese can just say: 一日にどれくらい日本語を勉強しますか。

Depending on the situation, the implied subject changes:

Teacher asking a student: “How long do you study Japanese per day?”
Student talking about themselves in a self‑introduction: “How long do I study Japanese per day?”

If you really want to say the subject, you could add it, but it often sounds stiff or unnatural:

あなたは一日にどれくらい日本語を勉強しますか。 – grammatically correct but overly direct; “あなた” is rarely used like “you” in normal conversation.
Better would be a name or title:
- 山田さんは一日にどれくらい日本語を勉強しますか。 – “Yamada, how much do you study Japanese a day?”

What does どれくらい mean, and how is it different from どのくらい or どれぐらい?

どれくらい is a general question word meaning “how much / how long / how many / to what extent”, depending on context.

In this sentence, with 勉強します and a time phrase, it is understood as “how long (in time)”.

About the variants:

どれくらい
どのくらい
どれぐらい
どのぐらい

All are very close in meaning, and in everyday conversation they are practically interchangeable.

Subtle points:

Textbooks often teach どのくらい first.
どれくらい feels slightly more casual/colloquial to some speakers but is still standard.
ぐらい vs くらい: ぐらい is just a voiced version; both are correct.

You can safely treat them all as meaning “how much / how long” and use whichever you’re most comfortable with. Native speakers mix them freely.

In this sentence, is どれくらい asking about hours, or something else?

In context, どれくらい is asking about duration (how many hours, how long).

Because the sentence has:

a time frame: 一日(に) – “in a day / per day”
a verb of activity: 勉強します – “study”

the natural interpretation is:

“How long do you study Japanese per day?” (i.e., how many hours/minutes)

If you want to be explicit and say “how many hours,” you can say:

一日にどれくらいの時間日本語を勉強しますか。
– “How much time per day do you study Japanese?”
一日に何時間日本語を勉強しますか。
– “How many hours per day do you study Japanese?”

But in ordinary conversation, 一日にどれくらい日本語を勉強しますか is enough; people will assume you mean time.

Why is 日本語 followed by を? Could we use other particles like で or に?

Here, 日本語 is the direct object of the verb 勉強します (“to study”), so it takes を, the object marker.

日本語を勉強します。
= “(I) study Japanese.”
(Japanese is what you’re studying.)

Contrast with other particles:

日本語で勉強します。
- Means: “I study in Japanese.”
- Here, 日本語で describes the language/means you use to study some other subject.
- For example: 日本語で数学を勉強します。 – “I study math in Japanese.”
日本語に勉強します。
- This is not natural Japanese.

So in 一日にどれくらい日本語を勉強しますか, を is the correct particle because 日本語 is what you are studying.

What form is 勉強します? How is it related to 勉強する?

勉強します is the polite present/future form (ます‑form) of the verb 勉強する.

勉強する – dictionary form, “to study”
勉強します – polite form, roughly “study / will study / do study”

Key points:

The ます‑form doesn’t distinguish between present and future.
- 明日日本語を勉強します。 – “I’ll study Japanese tomorrow.”
- 毎日日本語を勉強します。 – “I study Japanese every day.”
勉強 is originally a noun meaning “study,” and する means “to do.”
- 勉強する literally: “to do study”
- This is a common noun + する verb pattern in Japanese (e.g., 練習する “to practice,” 運転する “to drive”).

So the core of the sentence is:

日本語を勉強しますか。 – “Do you study Japanese?” / “Will you study Japanese?”
Adding 一日にどれくらい specifies how long per day.

Can I change the word order, like putting どれくらい or 一日 somewhere else?

Yes. Japanese word order is relatively flexible, as long as the particles stay with their words. Some common variations:

Original:
- 一日にどれくらい日本語を勉強しますか。
Move どれくらい earlier:
- どれくらい一日に日本語を勉強しますか。
- Understandable, but the original flows more naturally.
Put the time at the end:
- どれくらい日本語を勉強しますか、一日に。
- Grammatically possible, but sounds unusual or like you’re adding 一日に as an afterthought.
Put the object earlier:
- 日本語を一日にどれくらい勉強しますか。
- Also natural; many speakers would say this.

Most natural patterns keep time expressions (like 一日に, 毎日, 昨日) near the beginning of the sentence:

一日にどれくらい日本語を勉強しますか。
毎日どれくらい日本語を勉強しますか。
日本語を一日にどれくらい勉強しますか。

For learners, sticking close to the original order is a good, safe habit.

How would I answer this question in Japanese?

A common answer pattern is:

一日に X 時間（ぐらい）日本語を勉強します。
“I study Japanese about X hours per day.”

Examples:

一日に一時間ぐらい日本語を勉強します。
– I study Japanese about one hour a day.
一日に三時間日本語を勉強します。
– I study Japanese three hours a day.
一日に三十分だけ日本語を勉強します。
– I study Japanese only 30 minutes a day.

You can also be vaguer:

一日にあまり勉強しません。 – I don’t study much per day.
一日にたくさん日本語を勉強します。 – I study a lot of Japanese per day.

If you’re speaking casually with friends, you can drop ます and か:

Question (casual):
一日にどれくらい日本語勉強する？
Answer (casual):
一日に二時間ぐらい日本語勉強する。

What’s the difference between 一日にどれくらい日本語を勉強しますか and 毎日どれくらい日本語を勉強しますか?

They’re very close in meaning, and in many situations they can be used interchangeably.

一日にどれくらい日本語を勉強しますか。
- Literally: “How much do you study Japanese in one day?”
- Focuses on one day as a unit, i.e., “per day.”
毎日どれくらい日本語を勉強しますか。
- Literally: “How much do you study Japanese every day?”
- Focuses on the regularity (every day).

In actual conversation, both are usually understood as:

“How long do you study Japanese each day?”

If you want to emphasize that it’s a daily habit, 毎日 is a bit more explicit. If you’re talking more generally about how much fits into one day, 一日(に) highlights the time unit.

Are the spaces between the words normal in Japanese writing?

No. In standard Japanese writing, words are not separated by spaces. The sentence would normally be written as:

一日にどれくらい日本語を勉強しますか。

Spaces are added in teaching materials to help learners see each word:

一日　に　どれくらい　日本語　を　勉強します　か？

So:

With spaces – good for learners.
Without spaces – how native Japanese is actually written.

Why is か at the end? Could I just use rising intonation like in English?

In polite Japanese, か is the standard question marker at the end of a sentence.

勉強します。 – statement: “(I) study.”
勉強しますか。 – question: “Do (you) study?”

In very casual conversation, people can drop か and use rising intonation, especially with plain forms:

一日にどれくらい日本語勉強する？ – casual question, no か.

However:

With ます‑form (polite speech), you generally keep か to clearly mark a question:
- 一日にどれくらい日本語を勉強しますか。 ✅ natural polite question
- 一日にどれくらい日本語を勉強します。 ❌ looks like a statement, not a question

So for polite Japanese, always use か at the end for questions.