Learn Hardcore Japanese: ani ha ginkou de okane wo orosimasu. - My older brother withdraws money at the bank.

The particle は marks 兄 (あに, “older brother”) as the topic of the sentence. In Japanese, the topic is what you’re talking about, and it doesn’t always have to match the grammatical subject in English. Here, we’re saying “As for my older brother…,” then describing what he does.

Why is 兄 read as “あに” instead of “おにいさん”?

When referring to your own older brother in conversation, you typically use 兄 (あに). The form おにいさん is polite and often used when talking about someone else’s brother or when calling your own brother directly. Using あに is neutral when you’re just stating facts about your own sibling.

Why is 銀行 followed by で instead of に?

The particle で marks the location where an action takes place. Since the withdrawing action happens at the bank, you use 銀行で (“at the bank”). The particle に would be used to indicate movement toward a location (e.g., 銀行に行く, “go to the bank”), but here we’re describing an action occurring there.

What role does を play after お金?

The particle を marks the direct object of a verb. It tells us what is being withdrawn. So お金をおろします means “withdraw money,” with お金 as the thing acted upon.

What does the verb おろします mean, and why is it used here?

おろします (下ろします／降ろします／下ろす in dictionary form) means “to withdraw” or “to take down.” In banking contexts, it specifically means “to withdraw money.” The form おろします is the polite present tense, so the whole sentence is politely stating what the brother does.

Why is there an お in お金?

The prefix お is an honorific or polite marker attached to certain nouns. 金 by itself means “money,” but お金 is the standard polite form you’ll see most often in everyday speech.

How would you change the sentence into casual (plain) speech?

Replace the polite verb ending おろします with the plain おろす, and drop any unnecessary politeness. You get:
兄は銀行でお金をおろす。
This is appropriate among friends or in informal writing.