Die wetenskaplike ondersoek die brein.

Because die is the Afrikaans definite article, meaning the.

In Afrikaans, die is used for:

• singular nouns: die wetenskaplike = the scientist
• plural nouns: die wetenskaplikes = the scientists

So in Die wetenskaplike ondersoek die brein, both nouns are definite:

• the scientist
• the brain

Unlike some other languages, Afrikaans does not change the definite article for gender or case.

Here it is a noun: wetenskaplike = scientist.

That can confuse learners, because wetenskaplike can also be an adjective meaning scientific.

Compare:

• Die wetenskaplike ondersoek die brein. = The scientist examines the brain.
• Die wetenskaplike metode werk goed. = The scientific method works well.

So the role depends on the sentence.

Ondersoek is in the present tense.

In Afrikaans, present-tense verbs usually do not change for different subjects:

• Ek ondersoek = I examine
• Jy ondersoek = you examine
• Hy ondersoek = he examines
• Die wetenskaplike ondersoek = the scientist examines

So Afrikaans is simpler than English here, because there is no special -s ending like he examines.

Depending on context, the sentence could also be understood as:

• The scientist examines the brain
• The scientist is examining the brain

Afrikaans often uses the simple present where English might use either simple present or present continuous.

Because this is a normal main-clause statement, and Afrikaans usually follows SVO word order in simple sentences:

• Die wetenskaplike = subject
• ondersoek = verb
• die brein = object

So the structure is: The scientist / examines / the brain

This is very similar to English in a basic sentence like this.

You know from the word order.

In Die wetenskaplike ondersoek die brein:

• Die wetenskaplike comes before the verb, so it is the doer of the action.
• die brein comes after the verb, so it is the thing being examined.

If you reverse the nouns, the meaning changes:

• Die wetenskaplike ondersoek die brein. = The scientist examines the brain.
• Die brein ondersoek die wetenskaplike. = The brain examines the scientist.

Afrikaans usually relies on word order like English does.

Yes, but it would change the meaning.

• Die wetenskaplike = the scientist
• 'n wetenskaplike = a scientist

So:

• Die wetenskaplike ondersoek die brein. = The scientist examines the brain.
• 'n wetenskaplike ondersoek die brein. = A scientist examines the brain.

Notice that 'n is written with an apostrophe and is not capitalized, even at the beginning of a sentence in normal spelling. The following word is capitalized instead if needed.

Not always. Ondersoek can also be a noun, depending on context.

For example:

• as a verb: Hulle ondersoek die probleem. = They investigate the problem.
• as a noun: Die ondersoek duur lank. = The investigation takes a long time.

In your sentence, it is clearly a verb, because it comes after the subject and before the object.

A rough English-friendly guide would be:

dee VET-en-skap-li-keh un-der-SOOK dee brayn

A few useful pronunciation notes:

• w in Afrikaans sounds like English v
• oe sounds like oo in food
• ei in brein sounds somewhat like ay in day, though not exactly
• g in Afrikaans is usually a throaty sound, but there is no g in this sentence

This is only an approximation, but it can help you get started.

Because Afrikaans verbs are much less inflected than English verbs.

English:

• I examine
• he examines

Afrikaans:

• Ek ondersoek
• Hy ondersoek

The verb stays the same. This is one of the easier parts of Afrikaans grammar for English speakers.

Yes, often it could.

Afrikaans commonly uses the simple present in places where English might use either:

• examines
• is examining

So Die wetenskaplike ondersoek die brein may mean:

• The scientist examines the brain
• The scientist is examining the brain

Context usually tells you which is more natural.

It is capitalized only because it is the first word of the sentence.

Normally, the article is written lowercase:

• die wetenskaplike
• die brein

So if the phrase appeared in the middle of a sentence, you would write:

• Ek sien die wetenskaplike.

The capitalization here is just normal sentence capitalization, not a special grammar rule about the word die.