Learn Hardcore Indonesian: Penelitian kecil di kelas menunjukkan bahwa humor dapat menurunkan rasa cemas. - A small study in class shows that humor can reduce anxiety.

So penelitian kecil literally means study small, but in English we reverse it to small study. Putting kecil before the noun (kecil penelitian) would be ungrammatical.

Does penelitian kecil mean “a small study” or “a little bit of research”? Why not use sedikit?

Penelitian kecil is about the scale or scope of the study: a small-scale study.

kecil = small in size/scale/importance
sedikit = a small amount / a few

So:

penelitian kecil → a small (scale) study
sedikit penelitian → a little (amount of) research

In your sentence, it’s clearly a small study that was conducted in a classroom, not just “a bit of research” in general.

Why is it di kelas and not something like “di sebuah kelas” or “di kelas itu”? How specific is it?

Indonesian doesn’t require articles like a/the, so di kelas is flexible and can mean:

in class (in a general classroom situation)
in the class (a specific class already known from context)
in a class (some class, not specified)

If you need to be more specific, you can say:

di kelas itu = in that class
di kelas saya = in my class
di sebuah kelas = in a (certain) class (less common in speech, more formal/written).

In many contexts, simple di kelas is enough; the exact English equivalent (“in class” vs “in the class”) comes from context.

Does di kelas mean “in the classroom” or “during class”?

Di kelas can mean either, depending on context:

In the classroom (physical location): Mereka menunggu guru di kelas. – They waited for the teacher in the classroom.
During class (situation/activity): Kami tidak boleh makan di kelas. – We’re not allowed to eat in class.

In your sentence about a classroom study, both “in a classroom” and “in class” sound natural in English.

Why is there no word for “a” or “the” in penelitian kecil di kelas?

Indonesian doesn’t have articles like a/an/the. Nouns can be interpreted as singular or plural, definite or indefinite, based on context:

penelitian kecil di kelas could be a small classroom study or the small classroom study.

If you really need to emphasize definiteness, you can add words:

penelitian kecil itu = that small study / the small study
sebuah penelitian kecil = a( single) small study (formal, written style)

But in everyday usage, penelitian kecil di kelas is sufficient, and the listener will infer the English article from context.

What is the function of bahwa in menunjukkan bahwa humor dapat menurunkan rasa cemas? Is it necessary?

Bahwa introduces a clause that functions like “that” in English:

menunjukkan bahwa… = show that…

So your sentence part is:

menunjukkan bahwa humor dapat menurunkan rasa cemas
→ showed that humor can reduce anxiety.

In many cases, bahwa can be dropped in speech:

Penelitian kecil di kelas menunjukkan humor dapat menurunkan rasa cemas.

This is still grammatical, especially in informal or semi-formal Indonesian. Bahwa sounds more formal and explicit, similar to always including “that” in English.

What’s the difference between dapat and bisa here? Could we say humor bisa menurunkan rasa cemas?

Both dapat and bisa often translate as can in English, and you can say:

humor bisa menurunkan rasa cemas.

Subtle differences:

bisa: very common in everyday speech; neutral, informal to neutral.
dapat: slightly more formal; common in written language, academic or official contexts.

Because this sentence sounds like a reporting of research, dapat fits the slightly more formal, academic tone.

What exactly does menurunkan mean, and how is it different from mengurangi?

Menurunkan comes from turun (to go down), and literally means to lower or to bring down.

menurunkan rasa cemas = to lower/bring down feelings of anxiety.

Mengurangi comes from kurang (less), meaning to reduce or to lessen.

mengurangi rasa cemas = to reduce feelings of anxiety.

In this sentence, both menurunkan and mengurangi would be understood and acceptable.

menurunkan feels a bit more like lowering a level (like lowering anxiety, lowering temperature, lowering volume).
mengurangi focuses on reducing the amount or intensity.

Why is it rasa cemas and not just cemas or kecemasan?

cemas is an adjective = anxious.
rasa = feeling / sense.
rasa cemas literally = feeling (of being) anxious → anxious feelings.

kecemasan is a noun formed from cemas, and means anxiety (the state/condition):

menurunkan kecemasan = reduce anxiety.

All of these are possible:

menurunkan rasa cemas (reduce anxious feelings)
mengurangi rasa cemas (reduce anxious feelings)
mengurangi kecemasan (reduce anxiety)

Your sentence chooses rasa cemas to emphasize the felt experience (feelings) of anxiety rather than the abstract condition.

How do we know this sentence is talking about the past (a study showed), when there is no past tense marker?

Indonesian verbs generally do not change form for tense. Menunjukkan can mean:

shows (present)
showed (past)
will show (future), depending entirely on context.

To make the past explicit, speakers sometimes add time words or aspect markers:

Penelitian kecil di kelas itu telah menunjukkan bahwa… = That small classroom study has shown that…
Penelitian kecil di kelas kemarin menunjukkan bahwa… = The small study in class yesterday showed that…

In your isolated sentence, translators choose the English past showed because research reporting is usually about completed studies.

Is penelitian kecil di kelas singular or plural? Could it mean “small classroom studies”?

By itself, penelitian kecil di kelas is number-neutral. It can be interpreted as:

a small classroom study (singular)
small classroom studies (plural)

Context decides. If you really want plural, you can say:

penelitian-penelitian kecil di kelas = small classroom studies
beberapa penelitian kecil di kelas = several small classroom studies

In everyday usage and even academic writing, people often leave it as penelitian kecil and let context show whether it’s one study or more.

Why is there no subject pronoun like “it” before menunjukkan?

Indonesian does not use a dummy subject like English it. The subject here is the noun phrase:

Penelitian kecil di kelas = subject
menunjukkan = verb

So the structure is straightforward:

Penelitian kecil di kelas menunjukkan bahwa…
→ [The small study in class] showed that…

There’s no need (and no place) for an extra subject like it in Indonesian.

Does humor in Indonesian mean exactly the same as “humor” in English?

Indonesian humor is a loanword from European languages and is very close in meaning to English humor in the sense of funny things / comedy.

Humor dapat menurunkan rasa cemas. = Humor can reduce anxiety.

For “sense of humor”, Indonesians often say:

selera humor = sense of humor
- Dia punya selera humor yang bagus. – He/She has a good sense of humor.

So in your sentence, humor is understood as jokes, funny behavior, or comedic content that makes people laugh and thereby reduces anxiety.