Learn Hardcore Russian: Иногда сосед звонит мне вечером. - Sometimes the neighbor calls me in the evening.

Иногда means “sometimes.” It’s an adverb of frequency, so starting the sentence with Иногда highlights that the action occurs only occasionally. You can also move it elsewhere (e.g., Сосед мне иногда звонит вечером) without changing the core meaning.

How do I know that сосед is the subject of the sentence and why is it in the nominative case?

The subject—the one performing the action—is always in the nominative case in Russian. Here, сосед (“neighbor”) does the calling, so it appears in the nominative singular form.

Why is мне in the dative case rather than the accusative case?

The verb звонить (to call on the phone) takes the person being called in the dative case. In Russian you “ring to someone,” so you say звонить + дательный падеж. Hence, мне (“to me”) is dative, not accusative.

What is the function of вечером in this sentence and why is it in the instrumental case?

Time‑of‑day words like утром, днём, вечером typically use the instrumental case to mean “at [that part of the day].” So вечером here answers “when” the calling happens: “in the evening.”

Could I say по вечерам instead of вечером? What’s the difference?

Yes. Вечером (instr. sg.) refers to “in the evening” in a general or one‑off sense, or habitually in a neutral way. По вечерам (prep. pl.) emphasizes multiple evenings or a recurring pattern. So Иногда сосед звонит мне по вечерам feels more like “on several evenings” rather than a single evening.

Why is the verb звонит imperfective, and could I use the perfective позвонит here?

Звонит is imperfective, indicating a repeated or ongoing action. If you switch to perfective позвонит, you focus on single completed calls. Иногда сосед позвонит мне вечером is grammatically OK, but it frames each call as a distinct, finished event, rather than a habitual action.

Can I change the word order, for example: Сосед иногда мне звонит вечером or Сосед звонит мне иногда вечером?

Absolutely. Russian word order is flexible. Moving иногда or вечером shifts emphasis but keeps the meaning. Placing time expressions earlier highlights when; placing мне later or earlier can subtly shift focus on “me.”

Why is there no preposition before звонит мне? In English we say “calls me.”

In Russian, звонить governs the dative case directly without a preposition. It parallels verbs like помогать (“to help”) or угощать (“to treat someone to something”), which also use the dative for the person involved.