Soksi zake ziko chini ya kitanda.

In Swahili, possessives normally come after the noun they describe.

So the pattern is:

noun + possessive

That is why you get soksi zake = his/her socks, not the other way around.

This is very normal in Swahili:

• kitabu changu = my book
• viatu vyake = his/her shoes
• soksi zake = his/her socks

Zake means his/her/its in a form that agrees with soksi.

It does not mean their here. A very common learner mistake is to think zake means their just because English has a plural noun.

Here is the difference:

• zake = his/her/its
• zao = their

So:

• Soksi zake = his/her socks
• Soksi zao = their socks

Because soksi is a loanword, and many Swahili loanwords do not change form between singular and plural.

Instead, Swahili often shows the number through agreement words around the noun.

In this sentence, you can tell soksi is plural because of:

• za- in zake
• zi- in ziko

Compare:

• Soksi yake iko chini ya kitanda. = His/her sock is under the bed.
• Soksi zake ziko chini ya kitanda. = His/her socks are under the bed.

So the noun itself may stay the same, while the grammar around it tells you whether it is singular or plural.

Because both words are agreeing with the noun soksi as a plural class 10 noun.

Swahili uses noun-class agreement, so words connected to the noun often change form.

Here:

• za- in zake is the possessive agreement
• zi- in ziko is the subject agreement

Both point to the same thing: soksi is being treated as plural.

That is one of the big patterns in Swahili: words in the sentence often “match” the noun class of the subject noun.

Because this sentence is talking about location.

In Swahili, ni is mainly used for statements like:

• Yeye ni mwalimu. = He/She is a teacher.

But for saying where something is, Swahili commonly uses forms like:

• iko
• ziko
• uko
• kiko
• viko

So:

• Soksi zake ziko chini ya kitanda. = His/her socks are under the bed.

Here ziko means something like they are located or they are there.

Because the verb agrees with the subject, not with the noun inside the location phrase.

The subject here is:

Soksi zake

That is why the verb is ziko.

The phrase chini ya kitanda is just telling you the location: under the bed.
The noun kitanda is not the subject of the sentence, so it does not control the verb.

A rough structure is:

• Soksi zake = subject
• ziko = are
• chini ya kitanda = under the bed

Chini ya means under or below.

More literally:

• chini = bottom / lower part / below
• ya = of

So chini ya kitanda is literally something like the lower part of the bed or below the bed, but in natural English we usually translate it as under the bed.

This is a very common Swahili pattern:

• juu ya meza = on the table / above the table
• mbele ya nyumba = in front of the house
• ndani ya sanduku = inside the box

Because Swahili does not have articles like a, an, and the.

So kitanda can mean:

• a bed
• the bed

The exact meaning depends on context.

In a sentence like this, English often uses the bed because it sounds natural, but Swahili does not need a separate word for that.

Kitanda is a class 7 noun, and its plural is vitanda in class 8.

So:

• kitanda = bed
• vitanda = beds

This is the common ki-/vi- pattern:

• kitabu / vitabu = book / books
• kiti / viti = chair / chairs
• kitanda / vitanda = bed / beds

In your sentence, though, kitanda is just part of the location phrase, so it does not affect the form ziko.

Here are the useful contrasts:

• Soksi yake iko chini ya kitanda. = His/her sock is under the bed.
• Soksi zake ziko chini ya kitanda. = His/her socks are under the bed.
• Soksi zao ziko chini ya kitanda. = Their socks are under the bed.

Notice the changes:

• yake
  • iko for singular
• zake
  • ziko for plural
• zao for their

This is a good example of how Swahili shows meaning through agreement, even when the noun soksi itself does not change form.