Learn Hardcore Indonesian: Sejak hari itu, saya berusaha menguasai lebih banyak kosakata alam dalam bahasa Indonesia. - Since that day, I have tried to master more nature vocabulary in Indonesian.

Sejak means since (a point in time) and continuing from then until now (or until some later point). It highlights the starting point of a period.

Dari basically means from and is more neutral about time; it can be used for:

places: dari rumah (from home)
times: dari jam 8 (from 8 o’clock)

In time expressions, sejak is preferred when you want to express since X (up to now).

So:

Sejak hari itu, saya berusaha…
= Since that day, I have been trying… (ongoing effort implied)
Dari hari itu, saya berusaha…
This can be understood, but it sounds less natural and less precise than sejak in standard Indonesian when you mean since that day onward.

What exactly does sejak hari itu mean? Is it literally “since that day”?

Yes, sejak hari itu literally means since that day.

sejak = since
hari = day
itu = that

The phrase implies: starting on that specific day (previously mentioned in context) and continuing from then on.

Very similar alternatives:

sejak saat itu = since that moment
sejak waktu itu = since that time

All three are natural; sejak hari itu just highlights that it was a particular day.

Why is there a comma after Sejak hari itu? Is it required?

In Indonesian, a comma is usually placed after an introductory adverbial phrase (especially of time) when it’s at the beginning of a sentence.

So:

Sejak hari itu, saya berusaha… ✔
is the recommended punctuation.

Without the comma:

Sejak hari itu saya berusaha…
is still understandable and you will see it, but the version with a comma follows standard writing conventions and is clearer.

What is the nuance of berusaha compared to mencoba or just belajar?

berusaha = to make an effort, to strive.
It suggests serious, ongoing effort, not just trying once.
mencoba = to try (to attempt).
Often feels a bit lighter, like to give it a try.
belajar = to study / to learn.

In this sentence:

saya berusaha menguasai…
= I make an effort / I strive to master…
It sounds more determined than:
- saya mencoba menguasai… (I try to master…)
- saya belajar kosakata alam… (I study/learn nature vocabulary…), which focuses more on the activity of learning, not the effort or goal intensity.

Why is it berusaha menguasai and not berusaha untuk menguasai?

Both forms are possible:

berusaha menguasai…
berusaha untuk menguasai…

In modern Indonesian, when one verb follows another (like “try to ,” “want to ”), the untuk is often dropped, especially in everyday speech and writing.

So:

berusaha menguasai = perfectly natural and common
berusaha untuk menguasai = slightly more formal or explicit, but also correct

Many verbs can work this way:

ingin belajar / ingin untuk belajar
coba lakukan / coba untuk lakukan

What does menguasai mean here? Is it “to learn” or “to master,” and is it too strong?

Menguasai literally means to master, to have mastery over, to have control of.

In language-learning contexts:

menguasai kosakata = to master vocabulary (not just know a little)

So berusaha menguasai lebih banyak kosakata alam implies aiming for a fairly high level of competence, not just casually picking up a few words.

Alternatives with slightly different nuance:

mempelajari lebih banyak kosakata alam = to study more nature vocabulary
belajar lebih banyak kosakata alam = to learn more nature vocabulary

Menguasai is not “too strong” if you genuinely mean you want to master it; it just sounds more ambitious.

What does kosakata alam mean exactly? Why not kosakata tentang alam?

kosakata = vocabulary
alam = nature

So kosakata alam is understood as “nature vocabulary” or “vocabulary related to nature.” It’s like a noun–noun combination: nature-vocabulary.

kosakata tentang alam literally means vocabulary about nature. This is also correct and clear; it just uses a preposition tentang (about) to make the relationship explicit.

Nuance:

kosakata alam: more compact; sounds like a label for a category (like “medical vocabulary,” “legal vocabulary”).
kosakata tentang alam: a bit more descriptive, but still natural.

Both are fine; kosakata alam is shorter and stylistically neat.

Why is it lebih banyak kosakata alam, and not kosakata alam lebih banyak?

Lebih banyak means more (quantity) and normally comes before the noun phrase it modifies.

Pattern:

lebih banyak + [noun] = more [noun]

So:

lebih banyak kosakata alam = more nature vocabulary
(more items of that vocabulary)

If you say:

kosakata alam lebih banyak,
depending on context it can sound like:
“the nature vocabulary is more (plentiful)” compared to something else, as a predicate, not as “to learn more vocabulary.”

For example:

Kosakata alam lebih banyak daripada kosakata teknologi.
= Nature vocabulary is more abundant than technology vocabulary.

In this sentence, we want “to master more vocabulary,” so lebih banyak kosakata alam is the right structure.

Is kosakata always written as one word? I sometimes see kosa kata.

Both forms exist:

kosakata (one word) – this is the standard, recommended spelling in modern Indonesian.
kosa kata (two words) – older or less standard; still seen, but less preferred now.

In current formal writing and textbooks, you’ll usually see kosakata as one word. Using kosakata is the safer choice.

Why use dalam bahasa Indonesia instead of dengan bahasa Indonesia or pakai bahasa Indonesia?

They all can show language, but with different nuances:

dalam bahasa Indonesia = in Indonesian (language)
This is the standard, neutral way to specify the language of words, texts, or speech:
- kata ini dalam bahasa Indonesia = this word in Indonesian
- buku ini ditulis dalam bahasa Indonesia = this book is written in Indonesian
dengan bahasa Indonesia = with Indonesian
Sounds more like using Indonesian as a tool, often for speaking:
- Bicaralah dengan bahasa Indonesia yang baik dan benar.
pakai bahasa Indonesia = use Indonesian
Very colloquial:
- Kita pakai bahasa Indonesia saja. = Let’s just use Indonesian.

In this sentence:

kosakata alam dalam bahasa Indonesia = nature vocabulary in Indonesian
matches the idea of “vocabulary in a certain language,” so dalam is the most natural choice.

Could the sentence be shortened to Sejak hari itu, saya berusaha menguasai lebih banyak kosakata alam bahasa Indonesia without dalam?

You can say:

kosakata alam bahasa Indonesia

It would be understood, but it’s slightly more compact and a bit less clear structurally because you have three nouns in a row: kosakata–alam–bahasa Indonesia.

Using dalam makes the relationship explicit:

kosakata alam dalam bahasa Indonesia
= “nature vocabulary in the Indonesian language”

Native speakers do sometimes omit dalam in casual speech, but for clarity and standard style, dalam bahasa Indonesia is preferable, especially for learners.

Why is the pronoun saya used here instead of aku? Would aku be wrong?

Both saya and aku mean I, but they differ in formality:

saya = polite, neutral, suitable for formal or semi-formal situations, writing, talking to strangers, etc.
aku = informal, used with friends, family, or in casual settings.

In this sentence:

Sejak hari itu, saya berusaha… is neutral–formal and perfectly suitable for written examples, essays, or general explanations.
Sejak hari itu, aku berusaha…
is also grammatically correct; it just sounds more casual/intimate.

So aku is not wrong; it just changes the tone.

How does Indonesian show the “have been” idea in “Since that day, I have been trying…”? There is no tense marker in berusaha, right?

Correct: Indonesian verbs do not change form for tense (past, present, future).

Berusaha is just the base verb to make an effort, and the time/aspect is understood from context words like sejak (since), kemarin (yesterday), besok (tomorrow), etc.

In:

Sejak hari itu, saya berusaha menguasai…

the phrase Sejak hari itu tells us:

the action started in the past, and
is understood to continue from then on.

In English we use have been trying to show that ongoing aspect; in Indonesian, sejak + context does the job without changing the verb form. You could add sampai sekarang (until now) to emphasize continuity:

Sejak hari itu sampai sekarang, saya berusaha menguasai…
= Since that day until now, I have been trying to master…