Learn Hardcore Korean: oneureun saeroun munbeobeul yeonseuphaja. - Today let’s practice a new piece of grammar.

은/는 is the topic marker. 오늘은 means “as for today,” setting “today” as the topic and often implying contrast (e.g., today as opposed to other days). If you drop it and say 오늘 새로운 문법을 연습하자, it simply means “today, let’s practice new grammar,” with less of that contrastive “as for today” nuance. Using 오늘이 here would be ungrammatical because this sentence is a suggestion, not a statement where “today” is the subject.

Why is it 을 in 문법을 and not 를?

Use 을 after a noun ending in a consonant and 를 after a noun ending in a vowel. 문법 ends with the consonant ㅂ, so it takes 을 → 문법을. If the noun ended with a vowel (e.g., 한국어), you’d use 를 → 한국어를.

What nuance does -자 in 연습하자 have?

-자 is an informal, inclusive proposal meaning “let’s (you and I) ….” It’s used with friends, peers, or people of similar or lower status. Avoid it with strangers, superiors, or in formal situations.

How can I say this more politely or formally than 연습하자?

Common alternatives:

연습합시다. (formal polite “let’s”)
연습할까요? (polite “shall we?” sounding inviting)
연습하죠. (polite, soft suggestion; “let’s, shall we?”)
With honorifics for seniors: 연습하시죠.
To add a “try” nuance: 연습해 봅시다. / 연습해 볼까요?

What’s the difference between 새로운 문법 and 새 문법?

Both can mean “new grammar,” and they often overlap. Nuance:

새로운 문법 (from the adjective 새롭다) can suggest novelty as a property (“novel/innovative grammar”).
새 문법 (prenominal 새) often feels like “a newly introduced/another new grammar point.” In many contexts, either is fine.

How is 새로운 formed from 새롭다?

새롭다 is a ㅂ-irregular adjective (“to be new”). Before a vowel, the ㅂ changes to 우. The attributive ending for adjectives is -(으)ㄴ. So:

새롭 + (으)ㄴ → 새로우 + ㄴ → 새로운 (“new” before a noun).

Can I drop the object particle or rephrase the object part?

Yes, in casual speech you can:

Drop the particle: 문법 연습하자. (still natural in conversation)
Use a compound-noun pattern: 문법 연습을 하자. All are acceptable. 문법을 연습하자 explicitly marks “grammar” as the object; 문법 연습(을) 하자 frames it as the activity “grammar practice.”

Why is there no subject? Who is doing the practicing?

Korean often omits obvious subjects. The ending -자 inherently means “we (speaker + listener) should ….” You could add 우리 for emphasis: 오늘은 우리 새로운 문법을 연습하자, but it’s not required.

Can I change the word order?

Yes, Korean word order is flexible, and particles preserve roles:

Neutral: 오늘은 새로운 문법을 연습하자.
Without contrast on today: 오늘 새로운 문법을 연습하자.
Focusing the object: 새로운 문법은 오늘 연습하자. (“As for the new grammar, let’s practice it today.”)
Another focus: 새로운 문법을 오늘은 연습하자. All are grammatical; the nuance shifts with what you topicalize or front.

Is 연습하자요 correct?

Not in standard Korean. Don’t attach -요 to -자. Use a proper polite form instead, like 연습합시다, 연습할까요?, or 연습하죠. (Some dialects or playful speech may add -요, but it’s nonstandard.)

How is the sentence pronounced naturally?

오늘은 → RR: oneureun; sounds like [오느른] “oh-neu-reun”
새로운 → saeroun; [새로운] “sae-ro-un”
문법을 → munbeobeul; liaison makes it [문버블] “moon-buh-bul”
연습하자 → yeonseuphaja; due to ㅂ + ㅎ assimilation, it sounds like [연스파자] “yeon-seu-pa-ja” Together: approximately “oh-neu-reun sae-ro-un moon-buh-bul yeon-seu-pa-ja.”

How do I say “Let’s not practice new grammar today”?

Use -지 말자 for negative suggestions:

오늘은 새로운 문법을 연습하지 말자. To emphasize the contrast on “new grammar,” you could say: 새로운 문법은 오늘 연습하지 말자.

Could I just say 오늘은 연습하자 and drop 새로운 문법을?

Yes. 오늘은 연습하자 means “Let’s practice today,” without specifying what. The original sentence specifies the object (new grammar). Use whichever matches your intent.

Is there any tense marking here?

No. Suggestions with -자 don’t take tense markers. The time adverb (오늘은) and context supply the timing.