Mlango umefungwa sasa.

Because mlango belongs to the m-/mi noun class in Swahili, specifically class 3 in the singular. Nouns in this class take the subject agreement prefix u- when they are singular.

So in mlango umefungwa sasa:

• mlango = door
• u- = subject agreement for mlango
• -me- = perfect aspect
• fungwa = be closed / be shut

That is why you get umefungwa, not amefungwa.
For the plural, it changes:

• milango imefungwa = the doors are closed

So:

• singular: mlango umefungwa
• plural: milango imefungwa

Umefungwa can be broken down like this:

• u- = subject prefix agreeing with mlango
• -me- = perfect marker
• fung- = verb root from kufunga = to close / shut
• -w- = passive extension
• -a = final vowel

So the structure is roughly:

u-me-fung-w-a

This gives the idea has been closed or is closed.

A useful way to think of it is:

• kufunga = to close something
• kufungwa = to be closed

So mlango umefungwa literally has the sense of the door has become closed / has been closed.

It can suggest both, but most naturally it describes a present resulting state.

In other words, it implies that some closing happened earlier, and now the result is true: the door is closed.

That is why English often translates it as:

• The door is closed now

rather than the more literal but less natural:

• The door has been closed now

So the Swahili perfect here often works like a completed action with a present result.

Because Swahili does not always need a separate present-tense verb meaning is/are the way English does.

In this sentence, umefungwa is already a full verb form, so nothing extra is needed.

English needs:

• The door is closed now

But Swahili can simply say:

• Mlango umefungwa sasa

The idea of is is already built into the verbal structure.

Sasa means now. It adds a time reference and often suggests a contrast with an earlier situation.

So:

• Mlango umefungwa = The door is closed / has been closed
• Mlango umefungwa sasa = The door is closed now

The version with sasa can imply something like:

• it was open before, but now it is closed
• at this moment, the door is closed

Yes. Swahili word order is fairly flexible with adverbs like sasa.

These are all possible, though they may have slightly different emphasis:

• Mlango umefungwa sasa
• Sasa mlango umefungwa
• Mlango sasa umefungwa

The most neutral and natural version here is probably:

• Mlango umefungwa sasa

Putting sasa first often gives it more emphasis, like Now, the door is closed.

Yes. Mlango umefungwa is already a complete and natural sentence.

Without sasa, it simply means:

• The door is closed
• The door has been closed

Adding sasa just makes the time reference more explicit.

So both are correct:

• Mlango umefungwa
• Mlango umefungwa sasa

Usually, kufunga mlango most naturally means to close/shut the door.

Depending on context, it can sometimes be understood more strongly, but by itself it does not always specifically mean lock with a key.

So:

• Mlango umefungwa usually means The door is closed/shut
• if you want to make locked clearer, you often need more context or extra wording

This is similar to English, where shut and locked are not the same thing.

The plural of mlango is milango.

When the noun becomes plural, the agreement changes too:

• Mlango umefungwa sasa = The door is closed now
• Milango imefungwa sasa = The doors are closed now

Notice the change:

• singular class 3: u-
• plural class 4: i-

So:

• mlango umefungwa
• milango imefungwa

A simple pronunciation guide is:

• Mlango ≈ m-LAHN-go
• umefungwa ≈ oo-meh-FOONG-wah
• sasa ≈ SAH-sah

A few tips:

• ml at the start of mlango is pronounced together; the m is not silent
• ng in mlango is like the ng in finger, not like the ng in singer
• Swahili vowels are usually very regular:
  • a = ah
  • e = eh
  • i = ee
  • o = oh
  • u = oo

So the full sentence is pronounced smoothly and evenly, with fairly regular vowel sounds throughout.