Learn Hardcore Japanese: watasi ha kyousitu de eigo wo benkyousimasu.

Particle は marks the topic of the sentence. Here it tells us that “I” is what the speaker is talking about. Note: it’s pronounced wa when used as a topic marker.

Why is で used after 教室? Can I use に instead?

で indicates the location where an action takes place, so 教室で means “in/at the classroom” as the place of studying. に instead would mark a point of arrival or existence (“to the classroom” or “in the classroom” as a state), not the action’s site. To say “go to the classroom,” you’d use 教室に行きます.

What does を do after 英語?

Particle を marks the direct object of the verb. In this sentence, 英語 (English) is what is being studied.

Why is the verb 勉強します at the end of the sentence?

Japanese uses Subject–Object–Verb (SOV) word order, so the verb always comes last. You set up the topic, location, object, and then state the action.

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

勉強します is the polite present/future form (used in formal or polite settings). 勉強する is the plain/dictionary form (used casually or in writing).

Does 勉強します mean “I study” or “I will study”?

The Japanese present tense covers both habitual actions (“I study”) and future plans (“I will study”). Context or additional time words clarify which meaning is intended.

Can 私 be dropped? Why or why not?

Yes. Japanese often omits subjects when they’re clear from context. If it’s obvious who is doing the action, you can simply say 教室で英語を勉強します, and listeners will understand it’s “I” (or whoever the context implies).

Could I use 私が教室で英語を勉強します instead of 私は?

You can, but が marks the subject with emphasis, often when answering “Who?” Using は makes “I” the general topic rather than emphasizing the subject. So 私が～ might imply “It’s I who will study,” whereas 私は～ just states your topic.

Why aren’t there any articles like “a” or “the” before 教室 or 英語?

Japanese has no articles. Nouns stand alone without a, an, or the. Context tells you whether you mean something specific or general.