Learn Hardcore Japanese: syuugou no zikan ni okurete ha ikemasen. - You must not be late for the meeting time.

The particle の here connects two nouns, turning the first noun into a modifier of the second. In 集合の時間, 集合 (“gathering” or “assembly”) modifies 時間 (“time”), so the phrase literally means “the time of the gathering.”

What role does に play in 時間に?

The particle に marks a specific point in time. When you say 時間に, you’re indicating “at [that] time.” In this sentence, 集合の時間に means “at the gathering time.”

Why is 遅れる changed to the て-form 遅れて before adding は? Can’t we say 遅れるは?

Japanese prohibition patterns require the verb in its て-form before attaching は. You cannot say 遅れるは. Instead, you use 遅れては to set up the prohibition structure ～ては…, as in 遅れては　いけません.

What does the structure ～ては　いけません express, and how should I translate it?

The pattern Verb-ては　いけません expresses prohibition: “must not” or “may not.” So 遅れては　いけません means “You must not be late.”

Is 遅れては　いけません the only way to say “you must not be late”? What are some more casual or more polite alternatives?

No, there are several alternatives: • Casual prohibition: 遅れちゃダメ or 遅れるな
• Polite request: 遅れないでください (“please don’t be late”)
• Softer, more formal: 遅れないようにしてください (“please make sure not to be late”)

Can we drop the の in 集合の時間 and just say 集合時間? Are both correct?

Yes. 集合時間 is a tight compound noun meaning “gathering time,” and it’s perfectly acceptable. 集合の時間 is a bit more explicit or bookish, but both convey the same basic idea.

What part of speech is 集合 here, and how can you express “to gather” in Japanese?

In this sentence, 集合 is a noun (pronounced “しゅうごう”). To turn it into a verb meaning “to gather,” you attach する and say 集合する.