Sommige besonderhede is onbekend.

In Afrikaans, the present tense of to be is much simpler than in English. You use is with all subjects:

• ek is = I am
• jy is = you are
• hy/sy is = he/she is
• ons is = we are
• hulle is = they are

So Sommige besonderhede is onbekend is correct, even though besonderhede is plural.

Sommige means some.

In sentences like this, it usually refers to some of a group, so it often appears with a plural noun:

• sommige boeke = some books
• sommige mense = some people
• sommige besonderhede = some details

It does not change form for gender or number.

The singular is besonderheid.

So:

• 'n besonderheid = a detail
• besonderhede = details

This is a useful word pair to memorize because the plural is not just a simple -s form.

Afrikaans often leaves things a little more general unless you specifically want to make them definite.

• Sommige besonderhede = some details
• Sommige van die besonderhede = some of the details

Your sentence is more general. If you want to refer to a specific known set of details, sommige van die besonderhede is often more precise.

Here, onbekend is an adjective meaning unknown.

It comes after the verb is, so it is being used predicatively:

• Die naam is onbekend. = The name is unknown.
• Sommige besonderhede is onbekend. = Some details are unknown.

It describes the subject rather than standing directly before the noun.

In Afrikaans, adjectives often take -e when they come before a noun, but usually not when they come after a linking verb like is.

Compare:

• onbekende besonderhede = unknown details
• Die besonderhede is onbekend. = The details are unknown

So in your sentence, onbekend is correct because it comes after is.

Yes. Onbekend is made from:

• bekend = known / familiar / well-known
• on- = un-, not

So:

• bekend = known
• onbekend = unknown

This on- prefix is very common in Afrikaans, just like un- in English.

This is the normal basic Afrikaans sentence pattern:

Subject + verb + complement

So:

• Sommige besonderhede = subject
• is = verb
• onbekend = complement/adjective

It follows a very straightforward structure, much like English: Some details are unknown.

Yes. That means something like Some details remain unknown.

Compare:

• Sommige besonderhede is onbekend. = Some details are unknown.
• Sommige besonderhede bly onbekend. = Some details remain unknown.

The second version can sound a bit more formal or emphasize that the details are still not known.

A helpful rough guide is:

be-SON-der-HAY-de

More approximately in English-style spelling:

• be as in begin
• son like English sun
• der
• hede with a long ay sound in the stressed part

The stress is generally on son: beSONderhede.

Yes, depending on context. Onbekend can mean:

• unknown
• unfamiliar

For example:

• Die oorsaak is onbekend. = The cause is unknown.
• Die plek is vir my onbekend. = The place is unfamiliar to me.

In your sentence, unknown is the most natural meaning.

Not exactly.

• sommige besonderhede = some details
• 'n paar besonderhede = a few details

Sommige is less specific and can refer to an unspecified portion of the details. 'n paar suggests a small number more clearly.

So both are possible, but they are not always identical in nuance.