Aku mengetes lampu meja ini.

Aku is the informal first-person singular pronoun, so it sounds casual and everyday.
Saya is more polite or formal.

So:

• Aku mengetes lampu meja ini. = casual
• Saya mengetes lampu meja ini. = more formal/polite

A native speaker would choose between them based on situation, relationship, and tone.

Mengetes means to test.

It comes from the base word tes plus the verbal prefix meN-. In this sentence, it means the speaker is testing the lamp to see whether it works or how it performs.

In everyday Indonesian, mengetes is very common. A more formal or more native-sounding alternative is menguji.

So these are similar:

• Aku mengetes lampu meja ini.
• Aku menguji lampu meja ini.

But mengetes sounds more everyday and conversational.

This is because of how the prefix meN- behaves.

With many one-syllable roots, especially loanwords, Indonesian often uses menge-. Since tes is one syllable, it becomes:

• tes → mengetes

This same pattern appears in words like:

• cek → mengecek
• cat → mengecat
• bom → mengebom

So mengetes is the expected form for this type of root.

Because Indonesian prefixes are attached directly to the base word.

So:

• meN-
  • tes → mengetes

You do not normally write them separately. Indonesian affixes are part of the same word in standard spelling.

Indonesian often uses noun + noun combinations where the first noun is the main thing and the second noun describes its type or purpose.

So:

• lampu = lamp
• meja = table/desk
• lampu meja = a lamp for a table/desk, so desk lamp or table lamp

This does not usually mean a lamp on the table. If you wanted to say that, you would normally say:

• lampu di meja = the lamp on the table

That is an important difference.

In Indonesian, demonstratives like ini and itu usually come after the noun phrase they describe.

So:

• lampu meja ini = this desk lamp
• lampu meja itu = that desk lamp

This is normal Indonesian word order.

For English speakers, it feels reversed, because English says this desk lamp, but Indonesian says desk lamp this.

Yes, but it usually means something different.

• lampu meja ini = this desk lamp
• Ini lampu meja. = This is a desk lamp.

So when ini comes before the noun, it is often acting more like this is ... rather than directly modifying the noun inside the noun phrase.

That is why lampu meja ini is the correct form for this desk lamp.

Indonesian verbs do not change form for tense the way English verbs do.

So Aku mengetes lampu meja ini could mean different things depending on context, such as:

• I am testing this desk lamp
• I test this desk lamp
• I’m going to test this desk lamp

If you want to make the action clearly ongoing, you can add sedang:

• Aku sedang mengetes lampu meja ini. = I am testing this desk lamp.

Other time words can also clarify meaning:

• tadi = earlier
• sudah = already
• nanti = later
• akan = will

Because Indonesian usually does not use articles like English a/an and the.

Meaning is understood from context, word order, and words like ini or itu.

In this sentence, ini already makes the noun specific:

• lampu meja ini = this desk lamp

So nothing is missing. Indonesian simply handles definiteness differently from English.

In casual speech, yes, you may hear sentences like Aku tes lampu meja ini.

That sounds more colloquial and less fully marked grammatically.
Aku mengetes lampu meja ini sounds more complete as a regular active verb form.

So a simple way to think of it is:

• Aku tes ... = casual spoken shortcut
• Aku mengetes ... = fuller verb form
• Aku menguji ... = more formal or more standard-sounding

All three can appear, but they have slightly different tones.