itiniti nihongo wo benkyousimasu.

I study Japanese all day.

Breakdown of itiniti nihongo wo benkyousimasu.

• を: direct object particle
• 日に本ほん語ご: Japanese (language)
• 勉べん強きょうする: to study
• 一日いちにち: all day

Questions & Answers about itiniti nihongo wo benkyousimasu.

Why is there no word for “I” in this sentence?

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

• In English we must say “I study Japanese …”
• In Japanese, if it’s clear we’re talking about ourselves, just 日本語を勉強します is fine.

If you really want to include it, you can say:

• 私は一日日本語を勉強します。 – As for me, I will study Japanese for one day / all day.

But in normal conversation, 私は is usually omitted unless you need to contrast or emphasize “I” specifically.

What exactly does 一日 mean here?

一日 can mean two different things, with different readings:

1. いちにち – “one day / all day / for a day” (duration)
2. ついたち – “the first (day) of the month” (a calendar date)

In your sentence, there is no に particle after 一日, so it’s most naturally read:

• いちにち – “for one day” or “(for) the whole day”

So the sentence means something like:

• “(I) study Japanese for one whole day / all day.”

Why is there no particle after 一日? Shouldn’t it be 一日で or 一日間 or 一日に?

When 一日 (いちにち) expresses duration (“for one day”), it often appears without a particle, functioning like an adverb:

• 一日日本語を勉強します。
  → “(I) study Japanese for one day / all day.”

Some patterns and nuances:

• 一日日本語を勉強します。
  Duration (= for one day / all day). Natural, especially in speech.

• 一日間日本語を勉強します。
  Also “for one day”; 間 emphasizes the span as a period. Slightly more explicit.

• 一日で日本語を勉強します。
  “(I) will study Japanese in/within one day.”
  Focuses on finishing something within a day (e.g., finishing a task in a single day).

• 一日に日本語を勉強します。 (with に)
  Much more likely to be read ついたちに:
  “On the first (of the month), I will study Japanese.”

So in your sentence, the lack of a particle signals duration, not a calendar date.

Why do we use the particle を after 日本語?

を marks the direct object of the verb—the thing that the action is done to.

• 日本語を勉強します。
  Literally: “(I) do-study Japanese.”

So:

• 日本語 = Japanese (the language)
• を = object marker
• 勉強します = study

The pattern is:

• [thing being studied] + を + 勉強します
  
  • 英語を勉強します。 – I study English.
  • 歴史を勉強します。 – I study history.

Why is the verb 勉強します at the end? Can I put it earlier like in English?

Japanese basic word order is S–O–V (Subject–Object–Verb), not S–V–O like English.

Typical pattern:

• (私は)　一日　日本語を　勉強します。
  (Subject) Time Object Verb

The verb almost always comes at the end of a normal sentence. You can move time expressions and some other parts around for emphasis, but the verb stays last:

• 一日日本語を勉強します。
• 日本語を一日勉強します。
• (私は)日本語を勉強します、一日。 (very marked, usually only in spoken/emphatic speech)

All of these (except the last, which is more conversational/emphatic) have 勉強します at the end.

What “tense” is 勉強します? Does it mean “study” or “will study”?

勉強します is the polite non-past form. Japanese non-past can cover:

• Present/habitual:
  
  • “I study Japanese (regularly).”
• Future:
  
  • “I will study Japanese (tomorrow / later).”

Which nuance you get depends on context or extra time words:

• 毎日日本語を勉強します。 – I study Japanese every day. (habit)
• 明日日本語を勉強します。 – I will study Japanese tomorrow. (future)
• 一日日本語を勉強します。 – I’ll study Japanese for one day / all day. (often future or a plan)

What’s the difference between 勉強します and 勉強する?

They are the same verb, different politeness levels:

• 勉強します – polite form (used with strangers, in class, etc.)
• 勉強する – plain form (used with friends, family, in casual writing)

Example:

• Polite: 一日日本語を勉強します。
• Casual: 一日日本語を勉強する。

Meaning is the same; only the level of politeness changes.

Can I say 日本語を一日勉強します instead? Is the meaning different?

Yes, 日本語を一日勉強します is also natural.

Both are fine:

• 一日日本語を勉強します。
• 日本語を一日勉強します。

They both basically mean “(I) study Japanese for one day / for a whole day.”
Nuance:

• 一日日本語を勉強します。
  Slightly stronger focus on the length of time first (a whole day).

• 日本語を一日勉強します。
  Slightly more focus on what you’re doing (Japanese), then how long.

In normal conversation, the difference is subtle; both are correct.

If 一日 can mean “one day”, how do I say “every day” instead?

“Every day” is 毎日 (まいにち), not 一日.

• 毎日日本語を勉強します。
  → “I study Japanese every day.”

一日 (いちにち) by itself means “one day / for a day / all day (one day).”
So:

• 一日日本語を勉強します。 – I will study Japanese for one whole day / all day.
• 毎日日本語を勉強します。 – I study Japanese every day.

How do I know whether 一日 is read いちにち or ついたち?

You decide from context and particles:

• いちにち (duration: “one day / all day”)

  • Often appears without に:
    • 一日日本語を勉強します。 – for one day / all day
  • Or with 間:
    • 一日間日本語を勉強します。

• ついたち (date: “the first of the month”)

  • Usually appears with に when it’s a point in time:
    • 一日(ついたち)に日本語を勉強します。
      → On the first (of the month), I will study Japanese.

In your sentence, no に and the meaning is duration, so it’s いちにち.

If I want to say “all day long”, should I add 中 like 一日中日本語を勉強します?

Yes, 一日中 (いちにちじゅう) explicitly means “all day long / throughout the day.”

• 一日中日本語を勉強します。
  → “I will study Japanese all day long.”

Your original sentence:

• 一日日本語を勉強します。

can already be understood as “for one day” and often implies “all day” in context, but 一日中 makes the “all day long” idea very clear and strong.

Could I use 習います instead of 勉強します for “learn Japanese”?

You can, but the nuance is different:

• 勉強します – “study,” focusing on the act of studying (reading, doing exercises, etc.).

  • 日本語を勉強します。 – I study Japanese.

• 習います – “learn,” often implying learning from a teacher or instructor.

  • 日本語を習います。 – I learn Japanese (from someone / in a class).

In many beginner sentences about “studying Japanese,” 日本語を勉強します is the standard phrase.