Shati langu ni chafu leo.

In Swahili, possessives usually come after the noun, not before it.

So:

• shati langu = shirt my
• natural English translation = my shirt

This pattern is very common in Swahili:

• kitabu changu = my book
• jina lako = your name

So the basic pattern is:

noun + possessive

Because the possessive has to agree with the noun class of shati.

Shati is a singular noun in the ji/ma class pair, specifically class 5 in the singular. For that class, my takes the form langu.

So:

• shati langu = my shirt

If the noun were plural, the form would change:

• mashati yangu = my shirts

This is an important idea in Swahili: possessives do not have just one form. They change depending on the noun class of the thing being possessed.

Ni is the copula here — it works like English is.

So in this sentence:

• Shati langu ni chafu = My shirt is dirty

It links the subject (shati langu) with the description (chafu).

A useful thing to remember is that ni does not change for person or number in this kind of sentence:

• Mimi ni... = I am...
• Yeye ni... = He/She is...
• Mashati yangu ni... = My shirts are...

It actually is matching shati, but in this noun class the agreement is often not very visible.

Shati is class 5 singular, and with many adjectives, class 5 has a zero or invisible agreement marker. So the adjective appears in a plain-looking form:

• shati chafu = dirty shirt
• jina kubwa = big name
• tunda zuri = good fruit

You can see the agreement more clearly in the plural:

• mashati machafu = dirty shirts

So chafu is the correct agreeing form for singular shati, and machafu is the plural form.

Here is the breakdown:

• shati = shirt
• langu = my (agreeing with shati)
• ni = is
• chafu = dirty
• leo = today

So the structure is:

subject + copula + description + time word

That gives:

• Shati langu = the subject
• ni chafu = the description
• leo = when it is true

Leo is fairly flexible. Putting it at the end is very natural and neutral:

• Shati langu ni chafu leo.

But you may also hear:

• Leo shati langu ni chafu.
• Shati langu leo ni chafu.

The difference is mostly about emphasis:

• Leo... puts more focus on today
• final leo sounds more like a simple statement

For learners, the original sentence is a very good default pattern.

No. Swahili normally does not use articles like English the and a/an.

So shati can mean:

• a shirt
• the shirt
• just shirt, depending on context

In this sentence, langu already makes it specific, so English naturally translates it as my shirt.

This is normal in Swahili: you often do not need a separate word for the or a.

You would say:

Mashati yangu ni machafu leo.

Here is what changes:

• shati → mashati = shirt → shirts
• langu → yangu = possessive agrees with the plural noun class
• chafu → machafu = adjective agrees with the plural noun class
• ni stays the same
• leo stays the same

So:

• Shati langu ni chafu leo. = My shirt is dirty today.
• Mashati yangu ni machafu leo. = My shirts are dirty today.

A rough pronunciation guide is:

SHAH-tee LAH-ngoo nee chah-FOO LEH-oh

A few helpful notes:

• sh sounds like sh in shoe
• ch sounds like ch in church
• ng in langu is pronounced like the sound in finger, with a hard g
• Swahili vowels are usually clear and pure:
  • a as in father
  • e as in bed but often a bit tenser
  • i as in machine
  • o as in more without much glide
  • u as in flute

Swahili pronunciation is generally very regular, so once you know the sounds, reading is much easier than in English.