Learn Hardcore Swahili: Mimi na rafiki yangu tulibadilishana vitabu jana ili kila mmoja asome kitabu kipya. - My friend and I exchanged books yesterday so that each of us reads a new book.

In Swahili, when the subject is “X and I”, the verb normally agrees with “we” (sisi), because together you form a group that is speaking/acting.

Mimi na rafiki yangu tulibadilishana…
- tu- = we (subject agreement)
- -li- = past tense
- -badilishana = exchanged with each other

So the language thinks: “I and my friend = we”, so the verb must be in the first person plural.

If the subject were only your friend, you would say:

Rafiki yangu alibadilishana vitabu… (a- = he/she)

Is Mimi really necessary here, or could I just say Rafiki yangu na mimi tulibadilishana vitabu jana?

You can absolutely say:

Rafiki yangu na mimi tulibadilishana vitabu jana.

Both:

Mimi na rafiki yangu…
Rafiki yangu na mimi…

are grammatically fine. In practice:

Swahili often doesn’t need independent pronouns like mimi, wewe, yeye, because person and number are already shown in the verb (tuli- = we).
But pronouns are used:
- for clarity,
- for emphasis,
- or in coordinated phrases like mimi na rafiki yangu.

In very natural speech, many people might just say:

Tulibadilishana vitabu jana na rafiki yangu.
(“We exchanged books yesterday with my friend.”)

How is the verb tulibadilishana built, and what does the -shana part do?

Tulibadilishana is made of:

tu- = we (subject)
-li- = past tense
badilisha = to change
-na
- reciprocal extension → -shana (spelling change) = “to do to each other”

So:

kubadilisha = to change / to exchange (not necessarily mutually)
kubadilishana = to exchange with each other (reciprocal)

Tulibadilishana vitabu means “we exchanged books with each other,” not just “we changed books” in some vague way. The -shana marks that the action goes both ways: I give you a book and you give me one.

What is the difference between tulibadilishana vitabu and tulibadilisha vitabu?

Tulibadilishana vitabu
= We exchanged books with each other (I gave you one, you gave me one).
Tulibadilisha vitabu
Literally: We changed / altered books.
It could mean:
- we changed some books (e.g. edited/modified them),
- or we swapped books, but it does not explicitly say “with each other.”

If you want to be clear that this was a mutual exchange, tulibadilishana is the natural choice.

How does ili work in this sentence, and why do we use asome after it?

Ili introduces a purpose clause: “so that / in order that”.

Structure:

…jana ili = …yesterday so that
kila mmoja asome kitabu kipya = each person (should) read a new book.

In Swahili, after ili, the verb normally takes the subjunctive mood, which is marked by the final -e instead of -a:

asoma → not used
anasoma = he/she is reading (present indicative)
asome = (so that) he/she may read / should read (subjunctive)

So:

Ili asome = so that he/she may read
Ili tusome = so that we may read

Why is it asome (third person singular) and not wasome, even though kila mmoja refers to more than one person in total?

Kila mmoja means “each one / each person”, but grammatically it is singular:

kila = every/each
mmoja = one (class 1, used for people)

Because of this, the verb agrees in the singular:

kila mmoja asome… = each one (he/she) may read…

If you said kila mmoja wasome, it would sound wrong, like saying in English: “each person they read.” The idea “many people in total” is understood from context; grammatically it behaves as singular.

What exactly does kila mmoja mean, and can it be used without mentioning people explicitly?

Kila mmoja literally is “each one,” and in practice usually means “each person / everyone (individually)”.

You can use it without repeating mtu (person):

Kila mmoja aingie.
= Each one / everyone (one by one), come in.

In your sentence:

…ili kila mmoja asome kitabu kipya.
= so that each one (each person) may read a new book.

The people referred to (you and your friend) are clear from the earlier part of the sentence, so you don’t need to say kila mtu mmoja.

Why is it kitabu kipya but vitabu earlier? How do kitabu/vitabu and kipya relate?

Swahili uses noun classes, and nouns and adjectives must agree in class.

kitabu (book) is class 7
- singular: kitabu
- plural: vitabu (class 8)

In your sentence:

tulibadilishana vitabu = we exchanged books (plural)
kila mmoja asome kitabu kipya = each one may read a new book (singular)

Kipya is the adjective “new” agreeing with a class‑7 noun:

kitabu kipya = new book (class 7)
If it were plural:
- vitabu vipya = new books (class 8)

So:

kitabu kipya = one new book
vitabu vipya = new books

Why is it kitabu kipya (singular “a new book”) when earlier we had plural vitabu (“books”)? Aren’t they reading several new books?

The idea is:

You and your friend exchanged books (vitabu: maybe you each had one, or more).
The purpose clause focuses on what each person reads:
- kila mmoja asome kitabu kipya = each one should read a new book.

Grammatically:

kila mmoja = each one (singular)
So we match it with kitabu (singular) → one book per person.

If you wanted to say that each person reads several new books, you could say:

…ili kila mmoja asome vitabu vipya.
= so that each one may read new books.

Why is it rafiki yangu and not rafiki wangu? How do possessives work here?

Rafiki belongs to noun class 9/10 for agreement purposes. The possessive “my” must agree with the noun class.

Possessive pattern: [class agreement] + -angu

For class 9 (singular), the possessive use y-:
- rafiki yangu = my friend
- gari yangu = my car (also class 9)
For class 1 (person, singular):
- mtoto wangu = my child
For class 7 (kitabu):
- kitabu changu = my book

So rafiki yangu is correct because rafiki is treated as class 9, not class 1.

Where can jana (“yesterday”) appear in the sentence? Is tulibadilishana vitabu jana the only correct order?

Jana is quite flexible in position. All of these are natural:

Jana mimi na rafiki yangu tulibadilishana vitabu ili kila mmoja asome kitabu kipya.
Mimi na rafiki yangu tulibadilishana vitabu jana ili kila mmoja asome kitabu kipya.
Mimi na rafiki yangu jana tulibadilishana vitabu ili kila mmoja asome kitabu kipya.

Usually:

Putting jana near the verb or at the start of the sentence is most common.
You generally don’t put it between the verb and its object in a strange way, like:
- ✗ tulibadilishana jana vitabu (possible, but sounds less natural than tulibadilishana vitabu jana).

Could I replace ili kila mmoja asome kitabu kipya with something like ili kila mmoja asome kitabu kingine? What is the difference?

Yes, you could say:

…ili kila mmoja asome kitabu kingine.

Difference in meaning:

kitabu kipya = a new book (new in general, not necessarily previously known)
kitabu kingine = another book (a different one from the previous one)

So:

…tulibadilishana vitabu jana ili kila mmoja asome kitabu kipya.
= we exchanged books yesterday so that each one could read a new book.
…tulibadilishana vitabu jana ili kila mmoja asome kitabu kingine.
= we exchanged books yesterday so that each one could read a different / another book.

Both make sense, but kipya emphasizes “newness,” while kingine emphasizes “difference from the one they had before.”