Learn Hardcore Swahili: Asha alivaa sketi nyembamba yenye mistari meupe na ya bluu. - Asha wore a narrow skirt with white and blue stripes.

Both nyembamba and mwembamba come from the same adjective stem -embamba (thin / narrow / slim), but they agree with different noun classes:

mwembamba – used with class 1 (m-/m-) singular (usually people or animates)
- mtoto mwembamba = a thin child
wembamba – class 2 plural (people)
- watoto wembamba = thin children
nyembamba – used with class 9/10 (N-/N-) nouns (no visible prefix), which includes many loanwords
- sketi nyembamba = a narrow skirt
- barabara nyembamba = a narrow road

Since sketi is a class 9 noun, you use nyembamba, not mwembamba.

What does yenye mean in sketi nyembamba yenye mistari…?

Yenye is a kind of relative adjective meaning “having / with / that has.”

sketi nyembamba yenye mistari…
= a narrow skirt *with stripes…
= a narrow skirt **that has stripes…*

It links the noun (sketi) to something it possesses or contains (mistari).

You cannot simply say sketi nyembamba mistari…; you need a linker like:

sketi nyembamba yenye mistari… (skirt having stripes)
or sketi nyembamba ya mistari… (skirt of stripes / striped skirt)

Both are grammatical; yenye makes the “having” idea very clear.

Why is it specifically yenye, and not wenye or lenye?

Yenye agrees with the noun class of sketi.

sketi is a loanword in class 9/10 (N-class).
For class 9/10, the “with/having” form is yenye.

Very briefly, other classes look like this:

Class 1 (mtu): mwenye – mtu mwenye pesa (a person with money)
Class 2 (watu): wenye – watu wenye pesa (people with money)
Class 3 (mti): wenye – mti wenye matawi (a tree with branches)
Class 4 (miti): yenye – miti yenye matawi (trees with branches)
Class 5 (tunda): lenye – tunda lenye mbegu
Class 7 (kitu): chenye – kitu chenye rangi
Class 8 (vitu): vyenye – vitu vyenye rangi
Class 9/10 (sketi): yenye – sketi yenye mistari

So with sketi, yenye is the correct agreeing form.

What exactly is mistari? What is the singular, and what class is it?

Mistari means “lines / stripes”.

Singular: mstari = a line / a stripe
Plural: mistari = lines / stripes

Noun class:

mstari is class 3 (m-/m-)
mistari is class 4 (mi-)

You see the mi- at the beginning of mistari, showing the plural.

So mistari meupe na ya bluu = white and blue stripes.

Why is it mistari meupe and not mistari nyeupe? I learned nyeupe for “white.”

The basic adjective stem is -eupe (white), and it changes its prefix depending on the noun class.
Some common forms:

Class 1 (mtoto): mweupe – mtoto mweupe (a light‑skinned / white child)
Class 2 (watoto): weupe – watoto weupe
Class 3 (mstari): mweupe – mstari mweupe (a white line)
Class 4 (mistari): meupe – mistari meupe (white lines)
Class 9/10 (meza): nyeupe – meza nyeupe (a white table)

So:

nyeupe is for class 9/10 nouns.
meupe is the form that agrees with class 4 (mi-), which is what mistari belongs to.

That’s why we get mistari meupe, not mistari nyeupe.

(You may sometimes hear informal variation in real speech, but mistari meupe is the standard pattern.)

What does ya mean in mistari meupe na ya bluu? Why do we need it?

Ya is the -a “of” agreement form for class 4. It expresses association/possession:

mistari ya bluu = stripes *of blue / blue stripes*

Here, bluu is a color word borrowed from English, and it doesn’t change its form. So Swahili uses ya to link it to the noun and show agreement:

Noun: mistari (class 4)
“of” marker for class 4: ya
Color: bluu

So: mistari ya bluu (stripes of blue).

You would say, for example:

mistari ya kijani = green stripes
mistari ya manjano = yellow stripes

Why do we say meupe na ya bluu instead of just meupe na bluu?

Two different grammar behaviors are involved:

meupe is a true adjective (white), which agrees directly with the noun (mistari).
bluu is a borrowed color word from English, which usually behaves more like a noun; it doesn’t take Swahili agreement prefixes.

To connect bluu grammatically to mistari, we add the -a “of” form ya, which agrees with mistari:

mistari meupe = white stripes
mistari ya bluu = stripes of blue

When we join them:

mistari meupe na ya bluu
= stripes [that are] white and (that are) of blue
= white and blue stripes

Leaving out ya (mistari meupe na bluu) sounds incomplete/incorrect in standard Swahili.

Why does nyembamba come immediately after sketi, while yenye mistari… comes later? Could we move nyembamba?

Typical order in Swahili:

Noun
Basic describing adjectives (size, shape, etc.)
Extra descriptive phrases or relative parts (yenye…, ambayo…, etc.)

So:

sketi nyembamba yenye mistari…
= skirt (noun) + narrow (basic quality) + having stripes (extra detail)

You could say, for emphasis:

sketi yenye mistari meupe na ya bluu nyembamba

This is possible, but now nyembamba feels like an afterthought, describing the already-identified striped skirt. The most natural neutral order is what you have: sketi nyembamba yenye mistari….

Is sketi just English “skirt” in Swahili? How does it behave grammatically?

Yes, sketi is a loanword from English “skirt”, and it is very common in Swahili.

Grammar:

It belongs to class 9/10 (N-class).
Singular: sketi
Plural: also usually sketi (the form doesn’t change; agreement shows the plural)

Examples:

sketi nyembamba = a narrow skirt
sketi fupi = a short skirt
sketi ndefu = a long skirt

Because it is class 9/10, adjectives like nyembamba, nzito, nyeusi keep the same form for singular and plural:

sketi nyembamba (one narrow skirt)
sketi nyembamba (narrow skirts) – context shows plural.

Is there another common way to say “striped skirt” besides sketi … yenye mistari …?

Yes, several options are possible, with slightly different flavors:

sketi nyembamba ya mistari meupe na ya bluu
- Literally: a narrow skirt *of white and blue stripes*
- Uses ya mistari instead of yenye mistari.
sketi nyembamba yenye milia meupe na ya bluu
- milia = another word for stripes / bands.
More explicitly relative:
- sketi nyembamba iliyo na mistari meupe na ya bluu
- a narrow skirt that has white and blue stripes
- iliyo na is more formal/explicit than yenye.

Your original sentence with yenye mistari meupe na ya bluu is natural and common, especially in everyday description.