Learn Hardcore Indonesian: Lari sore membantu saya tidur.

Literally, lari = to run / running, and sore = late afternoon to early evening (roughly 3 p.m. to just after sunset).
So lari sore literally means “afternoon-evening running”, usually understood as “evening runs” or “running in the late afternoon/early evening.”
Indonesian time words like pagi, siang, sore, malam are a bit broader than English “morning/afternoon/evening/night.”

Is lari sore a noun phrase (“evening runs”) or a verb plus a time word (“run in the evening”)?

In this sentence, lari sore functions as a noun phrase, the subject of the sentence:

Lari sore (subject) membantu (verb) saya (object) tidur (complement).

You can think of lari sore here as “the activity of running in the evening.”
Indonesian often uses a bare verb root like lari as a noun for the activity (similar to English “running”).

Why is it lari and not berlari? Aren’t verbs supposed to use ber-?

Both are possible verbs:

lari = run (root; very common in speech)
berlari = run (more “complete” verb form, often a bit more formal or descriptive)

In everyday Indonesian, the root lari is totally acceptable as a verb, and as a noun (“running”) it must be the root form.
Here lari sore is an activity noun, so you don’t say berlari sore as a noun phrase; lari sore is the natural form.

Could I say Lari di sore hari membantu saya tidur instead?

Yes, Lari di sore hari membantu saya tidur is grammatically correct and means essentially the same thing: “Running in the late afternoon helps me sleep.”

lari sore = shorter, more natural and conversational.
lari di sore hari = a bit more explicit and slightly more formal or careful.

In speech, lari sore is more typical unless you want to emphasize the time more clearly.

Why is there no subject pronoun like Saya lari sore membantu saya tidur?

Because the subject of the sentence is the activity itself, not you as a person.

Lari sore = “Evening runs / evening running” (the activity)
membantu = “helps”
saya tidur = “me (to) sleep”

If you said Saya lari sore membantu saya tidur, it would be confusing: it sounds like “I run in the evening helps me sleep”, which is ungrammatical in both Indonesian and English.

What is the exact role of membantu here? Why not menolong?

Both membantu and menolong can be translated as “to help,” but they differ in usage:

membantu = help in a general, broad sense (make something easier, contribute to a result).
menolong = help in a rescue/aid sense (help someone in trouble, save, assist in a problem).

Here we mean “Evening runs help me sleep” in the sense of “contribute to / make it easier to sleep,” so membantu is the natural choice.
Menolong saya tidur would sound odd, almost like rescuing you so that you can sleep.

Why is it membantu saya tidur and not membantu tidur saya?

Saya is a pronoun (I, me), so it directly follows the verb as the object:

membantu saya = helps me
tidur here is a verb (“to sleep”), functioning as a complement to membantu saya.

Membantu tidur saya is not natural here; it would sound like “helps my sleep” where tidur is a noun, and you would normally clarify it more (e.g. membantu kualitas tidur saya = “helps the quality of my sleep”).
For the meaning “helps me sleep,” the pattern membantu + [person] + [verb] (like tidur) is common.

Could I say membantu saya untuk tidur? Is that correct?

Yes, Lari sore membantu saya untuk tidur is grammatically correct and understandable.
However, in everyday Indonesian, untuk in this pattern is often dropped:

More natural: membantu saya tidur
Slightly more formal/explicit: membantu saya untuk tidur

Both are accepted; omitting untuk is very common in spoken language.

Is tidur a verb or a noun here?

In this sentence, tidur functions as a verb: “to sleep.”
The structure is:

membantu (verb)
saya (object = me)
tidur (another verb, acting a bit like an infinitive: “(to) sleep”)

As a root word, tidur can be either a noun or a verb depending on context:

Saya mau tidur. = I want to sleep. (verb)
Kurang tidur itu tidak sehat. = Lack of sleep is unhealthy. (noun)

Here, the meaning and position after saya make it verbal.

Can I use aku instead of saya?

Yes, you can say Lari sore membantu aku tidur.

saya = more formal / neutral, safe in most situations (with strangers, at work, in writing).
aku = more informal / intimate, used with friends, family, or in casual contexts.

Grammar is the same; only the politeness level and tone change.

How would I say it in the past or future, since there’s no tense marking?

Indonesian verbs do not change form for tense. You keep the sentence structure and add time words if you need to specify time:

Dulu, lari sore membantu saya tidur.
= In the past, evening runs helped me sleep.
Besok, lari sore akan membantu saya tidur.
= Tomorrow, evening runs will help me sleep.

Without extra time markers, Lari sore membantu saya tidur is understood in a general, timeless sense: “Evening runs help me sleep (in general).”

Could I say Lari sore membuat saya mengantuk instead? What’s the nuance difference?

Yes, Lari sore membuat saya mengantuk is correct and natural.

membantu saya tidur = “helps me sleep” (focus on improving your ability to sleep).
membuat saya mengantuk = “makes me sleepy” (focus on causing the feeling of sleepiness).

Both can be used depending on what you want to emphasize: the result (sleep) or the feeling (sleepy).

Is it possible to say Lari sore membantu tidur saya and mean “Evening runs help my sleep”?

You can say Lari sore membantu tidur saya, and it’s grammatically possible, but it sounds a bit incomplete or unusual on its own.
More natural alternatives would clarify what aspect of sleep you mean, for example:

Lari sore membantu kualitas tidur saya. = Evening runs help the quality of my sleep.
Lari sore membuat tidur saya lebih nyenyak. = Evening runs make my sleep deeper/better.

For the simple idea “Evening runs help me sleep,” Lari sore membantu saya tidur is the most natural and direct.