Learn Hardcore Korean: ilju-il dongan maeil yeonseuphae.

동안 marks a duration and means for/during [a period of time]. So 일주일 동안 = for one week. It also works with clauses, meaning “while,” as in 공부하는 동안 = “while studying.” In this sentence, it restricts the timeframe to one week.

Is 매일 redundant with 일주일 동안?

Not redundant—매일 narrows the meaning to “every day within that week.”

일주일 동안 연습해 = Practice for a week (could imply continuously or generally during that week).
일주일 동안 매일 연습해 = Practice once each day for a week.
Compare 일주일 내내 연습해 = Practice all week long (emphasis on the entire span; can imply “constantly” more than “once per day”).

Who is the subject? I don’t see “I/you.”

Korean often drops obvious subjects. With 연습해 (casual), the default reading is a command to you: “Practice.” If the speaker is talking about themselves, they’d usually mark it:

나(는) 일주일 동안 매일 연습할 거야. = I’m going to practice every day for a week.

Is 연습해 a command or a statement?

As is, it’s most naturally a casual command (“Practice”). Depending on context and intonation, it could be a plan/statement, but for that Koreans prefer explicit future forms:

Command (casual): 연습해.
Statement about self (casual future): 연습할 거야/연습할게.
Suggestion (“let’s”): 연습하자.

How do I make it polite?

Use -요 or more formal endings.

Polite neutral: 일주일 동안 매일 연습해요.
Polite command/request: 일주일 동안 매일 연습하세요. or …연습해 주세요.
Formal: …연습합니다. / …연습하십시오.

Can I drop 동안?

Sometimes. With durations, 동안 is often optional in statements:

Past statement: 일주일 연습했어. (OK)
But in commands/plans, keeping 동안 (or -간) sounds clearer/natural:
Better: 일주일 동안 매일 연습해. / 일주일간 매일 연습해.
Avoid: 일주일 매일 연습해. (unnatural)

Is the word order “일주일 동안 매일” fixed? Can I say “매일 일주일 동안”?

Natural order is duration/scope first, then frequency: 일주일 동안 매일… This reads as “Within one week, every day…”
Putting 매일 first (매일 일주일 동안…) is odd because it makes “every day for one week” sound like a property of “every day,” not the duration. Stick to 일주일 동안 매일.

What’s the difference between 일주일, 한 주, and 한 주일?

일주일 (Sino-Korean number): “one week.”
한 주 (native number): also “one week,” common and natural.
한 주일: also used in everyday Korean, though some style guides consider it redundant.
Note: 일주 alone does not mean “one week” in everyday speech; you need 일주일 (or use 일주간 with -간).

Do I need any particles here?

Not necessarily. The bare time phrase is fine. You can add 은/는 for topic/emphasis:

일주일 동안은 매일 연습해. = As for that one week, practice every day.
If you specify an object, use 을/를: 발음을 매일 연습해.

Where would the object go if I add it?

Common and natural orders include:

일주일 동안 매일 발음을 연습해.
일주일 동안 발음을 매일 연습해.
Both are fine. Time expressions usually come early; 매일 sits near the verb or before the object.

How do I turn this into a question?

Add a question intonation or a question ending:

Casual yes/no: 일주일 동안 매일 연습해?
Polite: 일주일 동안 매일 연습해요?
Future plan (natural): 일주일 동안 매일 연습할 거야? / …연습할 거예요?

How can I say “exactly,” “about,” or “at least” a week?

Exactly: 딱 일주일 동안…
About/around: 일주일 정도(로/는) … or 대략 일주일 동안…
At least: 일주일은 … or 최소 일주일 동안…
Only: 일주일만 … / 일주일 동안만 …

How do I negate it?

Don’t practice (command): 일주일 동안 매일 연습하지 마.
Not/Don’t (statement): 일주일 동안 매일 연습 안 해. (casual) / …안 해요. (polite)
Can’t: …매일 연습 못 해. / …못 해요.

Is there a synonym for 매일?

Yes: 날마다 (native). It’s a bit more literary or expressive but common. You can also emphasize with 매일매일 (“every single day”).

일주일 동안 날마다 연습해.
일주일 동안 매일매일 연습해. (strong emphasis)

What’s the pronunciation like?

일주일 is pronounced roughly “il-ju-il” ([일주일]).
매일 is “mae-il” ([매일]).
연습해 often undergoes sound change to [연스패] in casual speech (the ㅂ meets ㅎ and becomes ㅍ), so it can sound like “yeon-seu-pae.” Careful speech may keep it closer to “yeon-seup-hae.”

Could I say “for the next week” or “this week” instead?

Yes, by specifying the reference:

Next week span: 다음 일주일 동안 매일 연습해. (for the next week)
This week: 이번 주(동안) 매일 연습해.
From Monday to Sunday: 월요일부터 일요일까지 매일 연습해.