Learn Hardcore Japanese: watasi ha yoru ni syousetu wo yomimasu.

は is the topic marker, showing that “as for me” is what we’re talking about. It sets “I” as the topic of the sentence. In contrast, が is the subject marker used when introducing new information or emphasizing the subject. Here, since you’re simply stating your habitual action (reading novels at night), は is the natural choice.

What does 夜に mean, and why is に necessary?

夜に means “at night.” The particle に marks a specific point in time. When you want to say you do something at a certain time (e.g. in the morning, at noon, at night), you attach に to the time word. Without に, 夜 can sometimes serve as a general time adverb (“at night”), but adding に makes it clear and precise: 夜に = “during the night.”

Why does 小説 take the particle を?

The particle を marks the direct object of a transitive verb. Here, the verb is 読みます (“read”), which requires an object: 小説 (“novel”). So 小説を読みます literally means “(I) read a novel,” with を showing what is being read.

Why is the verb 読みます at the end of the sentence?

Japanese follows a Subject-Object-Verb (SOV) word order. Verbs always come at or near the end. You first state the topic (私), then the time (夜に), then the object (小説を), and finally the action (読みます). Changing that order would sound unnatural or confusing in Japanese.

Why is 読みます instead of the dictionary form 読む?

読みます is the polite present/future form, used in everyday conversation with people you’re not extremely familiar with. 読む is the plain (dictionary) form, more casual or used in writing and among close friends. Both mean “read” in the non-past tense, but the level of politeness differs.

Can I omit 私は since it’s obvious who is doing the action?

Yes. Japanese often drops pronouns when context is clear. If you’re already talking about yourself, you can simply say 夜に小説を読みます and it will still mean “I read novels at night.” Omitting 私 makes the sentence more natural and concise.

This sentence uses the simple present tense. How would I say “I am reading a novel at night”?

To express the ongoing action “I am reading,” use the ～ている form:
私（は）夜に小説を読んでいます。
Here, 読んでいます shows that the action is in progress (“am reading”). You can still drop 私（は） if context is clear.

Can I switch the order of 夜に and 小説を, like 夜に読みます小説を or 小説を夜に読みます?

You can say 夜に小説を読みます (time first) or 小説を夜に読みます (object first), and both are grammatically correct. The nuance is subtle: putting the time first (夜に) emphasizes “at night,” while putting the object first (小説を) emphasizes “novels.” However, Japanese typically orders time-object-verb, so 夜に小説を読みます is the most natural.