Learn Hardcore Japanese: kodomo ha ie de hon wo yomimasu.

In this sentence, は marks 子供 as the topic (“as for the child…”). It contrasts or sets the stage for what you’re saying about the child, rather than introducing a new subject with が.

Why is 家 followed by で and not に?

The particle で indicates the location where an action takes place (“at home”). In contrast, に with a location often indicates a point of arrival or existence (“to home” or “at home/inside”), not the site of an ongoing action.

What role does を play after 本?

を marks 本 as the direct object of the verb 読みます. It tells you what is being read.

Why is the verb 読みます instead of 読む?

読みます is the polite present/future tense form of 読む. Learners use ～ます forms in formal or polite contexts, whereas 読む is the plain (dictionary) form used in casual speech or writing.

Could I use が instead of は: 子供が家で本を読みます?

Yes, grammatically it’s fine. が would simply mark 子供 as the subject, focusing on its existence or introducing it as new information. は instead marks it as the topic or contrasts it with something else.

Can particles like は, で, or を be dropped here?

In very casual speech you might omit particles, but dropping them can lead to ambiguity. Usually you keep は and を to make clear who’s doing what to what, and で to specify where the action happens.

Why does the verb come at the end of the sentence?

Japanese follows an SOV (Subject–Object–Verb) order. Placing the verb at the end is the standard structure, so listeners know all the context (who, what, where) before hearing the action.

Could I say うちで instead of 家で?

Yes. うち is a more colloquial word for “home,” whereas 家 (いえ) is slightly more formal or neutral. Either works with で to mean “at home.”

How would I say “The child is reading a book at home” (ongoing action)?

You’d use the ～ている form:
子供は家で本を読んでいます。
This emphasizes that the child is currently in the process of reading.