Learn Hardcore Japanese: watasi ha eki de tomodati wo matimasu.

は is the topic marker—it tells the listener “I” is what we’re talking about. It frames the sentence around 私. By contrast, が marks a new or emphasized subject. Since you’re simply stating what you do (you wait), は is the natural choice. In many cases you can even drop 私は entirely if it’s clear who the topic is.

How do the particles で and に differ when talking about locations, for example 駅で versus 駅に?

で marks the place where an action occurs.
- Example: 駅で待ちます means “I wait at the station.”
に marks a destination or a point of existence.
- Example: 駅に行きます means “I go to the station,”
- Example: 駅にいます means “I am at the station.”

Because 待つ (to wait) is an action, you use で for the location.

Why is 友達 marked with を? Shouldn’t “wait for someone” use に since it feels like “to” in English?

In Japanese 待つ is a transitive verb that directly takes the person you’re waiting for as a direct object. The direct-object marker is を. So you “wait someone” in Japanese rather than “wait to someone.” Thus 友達を待ちます is correct.

What is the role of ます in 待ちます, and how does it differ from 待つ?

ます creates the polite present/future form in Japanese.

待つ is the plain (dictionary) form.
待ちます is its polite counterpart.

Use 待ちます when speaking to strangers, superiors or in formal situations. Use 待つ in casual settings or when writing informal texts.

How would you express “I am waiting for my friend at the station” if you mean it’s happening right now?

You’d use the continuous ている form:

私は駅で友達を待っています。
This emphasizes the ongoing action (“am waiting”). The original 待ちます can imply a habitual action or a planned future action (“I will wait”).

Can I drop 私は? When is it okay to omit pronouns in Japanese?

Yes. Japanese often omits subjects and topics when they’re clear from context. If you’re already talking about yourself, you can simply say:

駅で友達を待ちます。
This is perfectly natural.

Is the word order flexible? Could I say 友達を駅で待ちます instead?

Japanese has a relatively free word order because particles show each word’s role. Both

駅で友達を待ちます
and
友達を駅で待ちます
are grammatical. The former (location before object) is slightly more common, but neither sounds odd.

Why are there no words for “the” or “a” before 駅? How do you express “the station” in Japanese?

Japanese doesn’t have articles like “the” or “a.” You simply use the noun and let context fill in the meaning. If you need to specify “that station” you can add a demonstrative:

あの駅で (at that station)
Otherwise 駅で can mean “at the station” or “at a station,” depending on the situation.