Learn Hardcore Japanese: watasi ha tosyokan de kanzi wo benkyousimasu.

は is the topic marker. It tells the listener that “私” (I) is the topic of the sentence—what the sentence is about. It’s different from the subject marker が, which introduces new or specific information.

Why is で used after 図書館 instead of に?

で marks the location where an action takes place (“at the library”).
に would indicate direction (“to the library”) or existence (“in the library”) rather than the site of your studying.

What function does を serve with 漢字?

を is the direct-object marker. It tells us that 漢字 (kanji) is what you are studying—the thing directly affected by the verb.

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

Japanese normally follows an S-O-V (subject-object-verb) order. Placing the verb last is the standard structure for Japanese sentences.

What tense and politeness level is 勉強します?

勉強します is the present/future tense in the polite form (also called the “ます-form”). It can mean either a habitual action (“I study kanji”) or a planned action (“I will study kanji”), depending on context.

Can I omit 私は and just say 図書館で漢字を勉強します?

Yes. Japanese often drops the topic when it’s clear from context. Without 私は, it’s still understood as “I study/ will study kanji at the library.”

What’s the difference between は and が?

は sets the topic or what the sentence is about (“as for X…”).
が marks the subject or highlights new or specific information.
In most study-action sentences like this, you use は to introduce the speaker as the topic.

Could you use a different verb form instead of 勉強します?

Yes. For casual speech, you’d say 勉強する (dictionary form). For past tense polite, 勉強しました (“studied”). The meaning stays “study (kanji)” but the tone and time reference change.