Learn Hardcore Indonesian: Saya membuka jendela karena udara di kamar terasa lembab. - I open the window because the air in the room feels humid.

Buka is the root word meaning “open.” In Standard Indonesian, when you turn a root into an active verb that takes an object, you add the me- prefix to signal the actor does the action. Hence buka → membuka (“to open [something]”). In casual speech you sometimes hear people drop the prefix and just say buka (“Saya buka jendela”), but in formal writing or teaching contexts, membuka is the correct transitive form.

Why the prefix mem- on buka? How does it work?

Indonesian uses me- prefixes to form active verbs. The exact shape (me-, mem-, men-, meny-, etc.) depends on the first letter of the root:
• buka takes mem- → membuka
• tulis takes men- → menulis
• nyanyi takes meny- → menyanyi
This system shows who is doing the action (active voice).

What is karena, and how is it used here?

Karena means “because.” It introduces a reason or cause and can be followed by a noun phrase or a full clause. In your sentence, karena links the action (Saya membuka jendela) to its cause (udara di kamar terasa lembab).

What does terasa mean, and why is it used before the adjective lembab?

Terasa comes from the verb rasa (“feel/taste”) in its ter- form, meaning “to be felt” or “to seem.” When you pair terasa with an adjective—here lembab (“humid”)—you get “feels humid.” It expresses a sensory impression rather than a hard fact.

Could I omit terasa and just say udara di kamar lembab? What nuance does terasa add?

Yes, udara di kamar lembab is grammatically correct and means “the air in the room is humid.” Adding terasa softens it to “the air in the room feels humid,” emphasizing your personal perception. Without terasa, it’s a straightforward statement of condition.

How can I tell that di kamar is a location phrase and not a passive verb marker?

In Indonesian, the preposition di indicating location is always written separately: di kamar (“in the room”). A passive di- prefix attaches directly to the verb with no space, e.g. dibuka (“was opened”). The space in di kamar tells you it’s a locative preposition, not the passive voice.

Why is the word order udara di kamar terasa lembab (noun + location + predicate) and not something else?

Here udara is your subject, di kamar modifies that subject (telling you which air you mean), terasa is the verb, and lembab is the adjective complement. Indonesian generally follows Subject–Modifier–Verb–Complement order. You could move di kamar to the end (udara terasa lembab di kamar), but placing it right after udara clearly ties the location to the air itself.

Is it possible to drop Saya in this sentence?

Yes. Indonesian often omits the subject pronoun if context makes it clear. Simply saying Membuka jendela karena udara di kamar terasa lembab is perfectly natural, especially in speech or casual writing.

Why specify udara? Could you say Saya membuka jendela karena kamar terasa lembab?

It’s more precise to refer to the air (udara), since “the room” itself isn’t literally humid—its air is. Saying kamar terasa lembab is understood but a bit less accurate. Learners often specify udara to describe how the air feels.