Learn Hardcore Indonesian: Sepanjang jalan, saya menarik napas dalam-dalam supaya tetap tenang. - Along the road, I take a deep breath so I stay calm.

Sepanjang means along/throughout the length of something (often something with a “path” or “extent,” like a road, river, journey, time period). In sepanjang jalan, it’s all along the road / the whole way.
Selama is more purely about duration in time: for/during (e.g., selama dua jam = for two hours).

Does jalan here mean road or walk/journey?

In sepanjang jalan, jalan most naturally means the road/way (the route). By extension it can also feel like the whole way / during the trip.
If you want to be explicit about the trip, you could say sepanjang perjalanan (throughout the journey).

Why is there a comma after Sepanjang jalan?

It’s optional, but common when the sentence starts with an introductory phrase.
Sepanjang jalan, sets the scene (Along the way, ...). In Indonesian writing, a comma is often used here similarly to English.

Can I omit saya? When do Indonesians drop it?

Yes, often. If the subject is clear from context, Indonesian frequently omits pronouns:
Sepanjang jalan, menarik napas dalam-dalam supaya tetap tenang.
Keeping saya is clearer and more neutral, especially in written Indonesian or when you want emphasis.

Why use menarik napas instead of just bernapas?

Both are possible, but they differ in nuance:

menarik napas = to take a breath / inhale (more deliberate, one “action” of taking a breath)
bernapas = to breathe (general ongoing action)
So menarik napas dalam-dalam emphasizes intentional deep breaths.

What’s the difference between napas and nafas?

Both refer to breath, but napas is the more standard spelling in modern Indonesian. Nafas is still seen and understood, but napas is generally preferred in formal writing.

What does the reduplication dalam-dalam do? Why not just dalam?

Reduplication here intensifies/iterates the quality: dalam-dalam means very deep / deeply (repeatedly).
So menarik napas dalam = take a deep breath (could be one deep breath)
menarik napas dalam-dalam = take deep breaths / take a really deep breath (stronger, often repeated).

How does supaya work? Is it the same as agar?

Supaya means so that / in order that. Agar is very similar and often interchangeable.
Rough guideline:

agar can sound slightly more formal/concise
supaya can feel a bit more conversational
Both fit this sentence.

Is supaya tetap tenang expressing purpose or result?

It primarily expresses purpose/intention: you take deep breaths in order to stay calm.
In context, it can also imply the expected result, but grammatically it’s framed as purpose.

What does tetap add? Could I just say supaya tenang?

tetap means to remain / still / continue to be.

supaya tenang = so that (I am) calm
supaya tetap tenang = so that (I) stay calm / remain calm (emphasizes maintaining calmness over time).

Why is tenang not marked as an adverb (like “calmly”)?

Indonesian often uses adjectives after linking ideas like tetap without changing form. tenang functions as the state/condition: (to) remain calm.
If you wanted “calmly” as a manner adverb, you might use dengan tenang (calmly), but that would be a different structure/meaning.

Can the word order be changed, like Saya menarik napas dalam-dalam sepanjang jalan?

Yes. Both are natural:

Sepanjang jalan, saya menarik napas dalam-dalam supaya tetap tenang. (sets the scene first)
Saya menarik napas dalam-dalam sepanjang jalan supaya tetap tenang. (focuses on the action first)
Meaning stays essentially the same; it’s mostly about emphasis and style.