Kosa nililolifanya jana sokoni ni kubwa.

The mistake that I made at the market yesterday is big.

Breakdown of Kosa nililolifanya jana sokoni ni kubwa.

• ni: to be
• kwenye: at
• soko: the market
• jana: yesterday
• kubwa: big
• kosa: the mistake
• nililolifanya: which I made

Questions & Answers about Kosa nililolifanya jana sokoni ni kubwa.

In this sentence, what is the subject and what is being said about it?

The subject is kosa (mistake).

The rest of the sentence nililolifanya jana sokoni ni kubwa tells us more about that mistake:

• nililolifanya jana sokoni = that I made yesterday at the market
• ni kubwa = is big / is serious

So the overall structure is:

• Subject: kosa
• Relative clause describing it: nililolifanya jana sokoni
• Predicate: ni kubwa

How is the long verb form nililolifanya built up, piece by piece?

nililolifanya can be broken down like this:

• ni- = I (1st person singular subject marker)
• -li- = past tense
• -lo- = relative marker agreeing with kosa (noun class 5)
• -li- = object marker for noun class 5 (referring back to kosa)
• fanya = do / make (verb root)

So nililolifanya literally means something like:

• ni-li-lo-li-fanya = I–past–which–it–did

Together with kosa, it gives: kosa nililolifanya = the mistake which I did (it).

Why are there two -li- parts in nililolifanya? Aren’t they the same thing?

They are two different pieces of grammar that just happen to look the same:

1. The first -li- (after ni-) is the past tense marker.

   • ni-li-… = I did …

2. The second -li- (before fanya) is the object marker for noun class 5.

   • It refers back to kosa (a class 5 noun).

So:

• ni-li-lo-li-fanya
  
  • ni- = I
  • -li- = past
  • -lo- = relative marker (for kosa)
  • -li- = it (object, again kosa)
  • fanya = do

Same sound, different function. Context and position tell you which -li- is which.

What exactly does the -lo- part in nililolifanya do?

-lo- is a relative marker that agrees with the noun being described by the relative clause, here kosa (class 5).

Different noun classes have different relative markers. For example:

• Class 5 (kosa, tunda): -lo-
  
  • kosa nililolifanya = the mistake that I made
• Class 7 (kitabu): -cho-
  
  • kitabu nilichokinunua = the book that I bought

So -lo- tells you “this is a relative clause describing a class-5 noun.”

Can I say kosa nililofanya jana sokoni instead of kosa nililolifanya jana sokoni?

Yes, you can. They are both grammatical, with a small structural difference:

1. kosa nililofanya jana sokoni

   • ni-li-lo-fanya (no object marker)
   • Literally: the mistake that I did yesterday at the market.

2. kosa nililolifanya jana sokoni

   • ni-li-lo-li-fanya (with object marker -li- referring to kosa)
   • Literally: the mistake that I did it yesterday at the market.

In practice:

• Both normally mean the same thing: the mistake I made yesterday at the market.
• The version with the object marker (nililolifanya) more explicitly reconnects the action to kosa. Many speakers use this pattern quite naturally in such relatives.

Is there a way to say this using ambalo, like in relative pronouns?

Yes. You can say:

• Kosa ambalo nililifanya jana sokoni ni kubwa.

Here:

• ambalo = which / that (relative pronoun agreeing with a class 5 noun)
• nililifanya = ni-li-li-fanya (I–past–it–did), where -li- as object marker again refers back to kosa.

Differences:

• kosa nililolifanya … uses the short relative marker -lo- inside the verb.
• kosa ambalo nililifanya … uses a separate relative pronoun ambalo plus a regular verb.

Both are correct. The shorter kosa nililolifanya … is very natural and common in everyday Swahili.

How would the sentence change if we talked about mistakes (plural) instead of a mistake?

Plural of kosa (class 5) is makosa (class 6). The agreement changes in the relative and in the adjective:

• Makosa niliyoyafanya jana sokoni ni makubwa.
  
  • makosa = mistakes
  • niliyo-yafanya = that I made (referring to class 6)
    
    • ni-li-yo-ya-fanya
      
      • ni- = I
      • -li- = past
      • -yo- = relative marker for class 6
      • -ya- = object marker for class 6
      • fanya = do
  • ni makubwa = are big/serious

So the relative marker and the object marker both change from -lo- / -li- (class 5) to -yo- / -ya- (class 6).

Why is it sokoni and not just soko?

soko = market (the noun itself)
sokoni = at the market / in the market

The -ni ending is a locative suffix, often meaning:

• in, at, or to a place

So:

• sokoni = at the market
• nyumbani (from nyumba) = at home / to home
• shuleni (from shule) = at school

In jana sokoni, sokoni answers “where?” about the action nililolifanya.

Can jana and sokoni swap places, or must it be jana sokoni?

They can swap; both are possible:

• Kosa nililolifanya jana sokoni ni kubwa.
• Kosa nililolifanya sokoni jana ni kubwa.

Swahili generally allows flexible order for time and place adverbials. The most common and neutral order is often:

• Time → Place

So jana sokoni (yesterday at the market) is slightly more typical, but sokoni jana is also understood and accepted in many contexts.

Why do we need ni before kubwa? Could you just say kosa … kubwa?

In this sentence, ni is functioning like the English “is”:

• kosa … ni kubwa = the mistake … is big/serious.

Standard structure for “X is Y” in Swahili is:

• X ni Y
  
  • Juma ni mgonjwa. = Juma is sick.
  • Gari hili ni kubwa. = This car is big.

You might hear kosa … kubwa without ni in very informal or elliptical speech, but the clear, standard predicative pattern uses ni:

• kosa … ni kubwa = the mistake … is big.

Why doesn’t kubwa change form to agree with kosa?

As a predicate adjective (after ni), kubwa usually appears in this plain form, regardless of the noun class:

• kosa ni kubwa = the mistake is big
• gari ni kubwa = the car is big
• nyumba ni kubwa = the house is big

When kubwa is used directly before a noun (attributively), agreement patterns can show up via noun-class prefixes or in the plural:

• kosa kubwa = a big mistake
• makosa makubwa = big mistakes
• gari kubwa = a big car
• magari makubwa = big cars

So in your sentence, kubwa is not modifying kosa directly; it is the predicate after ni, so it stays in that basic form.