Fumbo ni gumu.

• fumbo = riddle, puzzle, or enigma
• ni = is / are in this kind of sentence
• gumu = difficult, hard

So the structure is literally:

• Fumbo = riddle
• ni = is
• gumu = difficult

That gives Fumbo ni gumu = The riddle is difficult or A riddle is difficult, depending on context.

In this sentence, ni works like a copula, similar to English is / am / are.

So:

• Fumbo ni gumu = The riddle is difficult

Without ni, you would not normally have a complete sentence with this meaning.

Compare:

• fumbo gumu = a difficult riddle
  
  • this is just a noun phrase
• Fumbo ni gumu = The riddle is difficult
  
  • this is a full sentence

So ni is what turns the idea into “X is Y.”

In Swahili, adjectives usually come after the noun they describe.

So:

• fumbo gumu = difficult riddle
• literally: riddle difficult

This is normal Swahili word order. English usually puts adjectives before nouns, but Swahili usually puts them after.

Swahili adjectives often change form to agree with the noun class of the noun they describe.

Fumbo belongs to the ji-/ma- noun class group, and in the singular, adjectives like -gumu often appear simply as gumu.

So:

• fumbo gumu = difficult riddle
• mafumbo magumu = difficult riddles

Notice the plural:

• fumbo → mafumbo
• gumu → magumu

That ma- on magumu matches the plural noun class.

The plural is:

Mafumbo ni magumu.

Breakdown:

• mafumbo = riddles
• ni = are
• magumu = difficult

So:

• Fumbo ni gumu. = The riddle is difficult.
• Mafumbo ni magumu. = The riddles are difficult.

This is a good example of noun-adjective agreement in Swahili.

Fumbo most often means riddle, but it can also mean something like:

• mystery
• puzzle
• enigma
• something hard to understand

So depending on context, Fumbo ni gumu could suggest:

• The riddle is difficult
• The mystery is hard to understand
• The puzzle is difficult

The exact meaning depends on the situation.

Yes. Gumu can mean both:

• difficult
• hard

Just like English hard, it can be used in more than one way depending on context.

For example, it may describe:

• something mentally difficult
• something tough or severe
• sometimes even something physically hard, depending on usage

In Fumbo ni gumu, the most natural meaning is difficult.

No separate word appears here for the or a/an.

Swahili usually does not use articles the way English does.

So fumbo can mean:

• a riddle
• the riddle

The context tells you which one is meant.

That is why Fumbo ni gumu can be translated as either:

• A riddle is difficult
• The riddle is difficult

In most real contexts, The riddle is difficult is the more natural translation.

A simple pronunciation guide is:

FOOM-boh nee GOO-moo

A few helpful points:

• fu sounds like foo
• mbo is pronounced clearly, with the m and b both heard
• ni sounds like nee
• gu sounds like goo
• mu sounds like moo

Swahili pronunciation is generally very regular, and each vowel is usually pronounced clearly:

• a = ah
• e = eh
• i = ee
• o = oh
• u = oo

Yes, but it means something slightly different.

• Fumbo gumu = a difficult riddle
  
  • this is a noun phrase
• Fumbo ni gumu = The riddle is difficult
  
  • this is a full sentence

So if you are naming or describing an object, Fumbo gumu is fine.

If you want to say that the riddle is difficult, use ni:

• Fumbo ni gumu

This is a very common pattern:

noun + ni + adjective

Examples:

• Chakula ni kitamu. = The food is delicious.
• Swali ni rahisi. = The question is easy.
• Fumbo ni gumu. = The riddle is difficult.

So this is a useful basic pattern for making simple statements:

X ni Y = X is Y

It works with nouns, adjectives, and many simple descriptions.