Chaji ya simu ni ndogo.

It is a noun phrase meaning the phone’s charge or the charge of the phone.

• chaji = charge
• ya = of / belonging to
• simu = phone

So chaji ya simu literally works like charge of phone.

Ya is the genitive/possessive linker. It connects two nouns, like of in English.

So:

• chaji ya simu = charge of the phone
• mlango wa nyumba = door of the house
• kitabu cha mwanafunzi = book of the student

In this sentence, ya links chaji with simu.

Because this linker must agree with the first noun, the thing being described, not the second noun.

Here the first noun is chaji, which behaves like a class 9 noun, so the correct linker is ya.

That is why you get:

• chaji ya simu

not:

• chaji wa simu
• chaji cha simu

This is a very common Swahili pattern: the connector changes according to noun class.

Ni is the copula, meaning is / are.

It links the subject to the description:

• Chaji ya simu = the phone’s charge
• ni ndogo = is low / is small

So ni is the word that turns the phrase into a full sentence.

In standard Swahili, you normally keep ni here.

• Chaji ya simu ni ndogo. = The phone charge is low.

If you remove ni, the result does not sound like the same complete statement in standard usage. It can sound incomplete or like a noun phrase rather than a full sentence.

So for learners, it is best to use ni in a sentence like this.

Because -dogo basically means small / little, but in context it can also mean low when talking about an amount or level.

So with battery or phone charge:

• chaji ni ndogo = the charge is low

This is similar to how English sometimes uses a size word metaphorically:

• a small amount
• low battery
• little charge left

So ndogo is not wrong here; it is a natural extension of small/little to low.

It describes chaji, not simu.

The sentence is saying that the charge is low, not that the phone is small.

So the structure is:

• Chaji ya simu = the phone’s charge
• ni ndogo = is low/small

Even though simu is inside the phrase, the main noun being talked about is chaji.

The adjective stem is -dogo. In Swahili, adjectives usually agree with the noun class of the noun they describe.

Here, chaji is treated as a class 9 noun, and class 9 often gives the adjective a nasal prefix. So:

• -dogo becomes ndogo

That is why you see ndogo rather than just dogo.

No.

• chaji = charge, charging, charge level
• betri = battery

So Chaji ya simu ni ndogo means the charge level is low, not that the battery itself is physically small.

No. Swahili usually does not use articles like a, an, or the.

So:

• simu can mean a phone or the phone
• chaji ya simu can mean phone charge, the phone’s charge, or a phone’s charge

The exact meaning is understood from context.

Partly yes, partly no.

The full sentence order is:

• Chaji ya simu = the phone’s charge
• ni = is
• ndogo = low

So the overall sentence is fairly close to English:

• The phone’s charge is low

But inside the noun phrase, Swahili uses noun + ya + noun:

• chaji ya simu = charge of phone

This is different from English, which often prefers phone charge or the phone’s charge.

You can say:

Chaji ya simu si ndogo.

Here si means is not / are not.

So this means:

The phone’s charge is not low
or
The phone’s charge is not small

Normally, in this sentence, chaji is understood as charge level, especially because ndogo makes sense with that meaning.

If you wanted to talk about a phone charger, speakers often say something like:

• chaja ya simu
• charger ya simu in casual speech

So in Chaji ya simu ni ndogo, learners should understand chaji as charge, not charger.