Learn Hardcore Swahili: Siyo tu leo tunarudia msamiati, bali pia tunatunga sentensi na mistari mipya. - Not only are we reviewing vocabulary today, but we are also creating new sentences and lines.

Siyo tu (not only) leo tunarudia msamiati (today we are reviewing vocabulary),
bali pia tunatunga sentensi na mistari mipya (but we are also composing sentences and new lines/verses).

This pattern is common and quite fixed in Swahili when you want to emphasize that you are doing more than one important thing:

Siyo tu anasoma, bali pia anafanya kazi.
Not only is he/she studying, but he/she is also working.

You can reuse Siyo tu … bali pia … in many contexts like this.

Why does the sentence use Siyo tu instead of just Si or Si tu?

All three forms exist, but they have different common uses and levels of emphasis:

Si
Basic negation for many things, including equational sentences:
- Si kweli. = It is not true.
- Si leo. = It’s not today.
Si tu
Literally “not only”. In speech and writing, many people say/write si tu and siyo tu almost interchangeably in this pattern.
Siyo tu
- Built from si
  - yo (a pronominal element often linked with ni “to be”).
- In practice, siyo tu often feels a bit more emphatic or clearer as a chunk meaning “not only”.
- It’s very common in the fixed pattern Siyo tu … bali pia ….

You could also hear:

Si leo tu tunarudia msamiati, bali pia tunatunga sentensi na mistari mipya.

This rearrangement is possible and grammatical, but Siyo tu leo … is a very natural and idiomatic way to kick off the not only … but also … contrast.

What exactly does bali mean, and how is bali pia different from lakini or ila?

All of these words can be translated as “but”, but they are not used the same way.

lakini = but / however
Neutral contrast:
- Nataka kwenda, lakini sina muda.
  I want to go, but I don’t have time.
ila = but / except
Also contrast, sometimes with a small nuance of exception:
- Wote walienda, ila yeye.
  Everyone went, except him/her.
bali = but rather / but instead
Used especially when you want to correct, replace, or contrast strongly:
- Si kumi, bali kumi na mbili.
  Not ten, but rather twelve.

In the pattern Siyo tu … bali pia …:

bali keeps that “corrective/contrast” flavour: “not only X, but rather also Y.”
pia means “also” / “too” / “as well”, so bali pia together gives something very close to “but also”.

Using lakini here would sound off; the fixed idiomatic pair is Siyo tu … bali pia …, not Siyo tu … lakini pia ….

Why is leo placed right after Siyo tu and before tunarudia? Could it go somewhere else?

Yes, leo (today) is relatively flexible in position. In the given sentence:

Siyo tu leo tunarudia msamiati, bali pia …

the focus is something like “Not only today are we reviewing vocabulary …” but it is usually interpreted more simply as:

“Not only (are we) reviewing vocabulary today, but also …”

You could also say:

Leo si tunarudia tu msamiati, bali pia tunatunga sentensi na mistari mipya.
Leo tunarudia si tu msamiati, bali pia tunatunga sentensi na mistari mipya.
Tunarudia msamiati leo, na pia tunatunga sentensi na mistari mipya. (loses the specific “not only … but also …” pattern)

All of these are grammatical but have slightly different emphasis and flow.

Placing leo early (as in the original) is very natural, because time expressions (like leo, kesho, jana) commonly appear near the beginning of a sentence in Swahili.

What tense is tunarudia and tunatunga, and why is that tense used here?

Both tunarudia and tunatunga are in the present tense:

tu- = we
-na- = present tense marker
-rudia / -tunga = verb roots

So literally:

tunarudia = we review / we are reviewing
tunatunga = we compose / we are composing

The -na- tense in Swahili is quite flexible. It can express:

Present continuous: an action happening right now
- Sasa tunarudia msamiati.
  Right now we are reviewing vocabulary.
Regular / habitual actions: what usually happens
- Kila siku tunarudia msamiati.
  Every day we review vocabulary.
Near future, especially when context makes that clear
- In a classroom plan for today, leo tunarudia msamiati can be understood as “today we are going to review vocabulary.”

In the sentence you gave, given the context is likely a lesson plan for today, -na- naturally covers “what we do / are doing in today’s lesson.”

What does the verb kurudia mean exactly, and why is there no object marker like tunau-rudia msamiati?

Kurudia means “to repeat / to go over again / to review”.

Pattern of use:

kurudia kitu = to repeat/review something
e.g. Kurudia msamiati = to review vocabulary.

About the object marker:

You can add an object marker when the object is definite, already known, or strongly emphasized:
- Tunarudia msamiati.
  We are reviewing vocabulary. (general: vocab in this lesson)
- Tunau-rudia msamiati ule tulioujifunza jana.
  We are reviewing that vocabulary we learned yesterday.
  (-u- is the object marker agreeing with msamiati.)

In your sentence, msamiati is already explicit; it’s simply the content of the lesson, so the object marker is not required. Leaving it out is normal and sounds natural.

What noun class is msamiati, and what is its plural form?

Msamiati belongs to the m-/mi- (3/4) noun class:

Singular: m-samiati
Plural: mi-samiati

So:

msamiati = vocabulary (singular form, but often used as a mass/collective noun, like “vocabulary” in English)
misamiati = vocabularies / lists of vocabulary (less common in everyday speech, more in technical or academic contexts when you really mean multiple separate vocabularies or sets)

Agreement for class 3/4:

Singular (3): m- / u- in some agreements
Plural (4): mi-

However, because msamiati is often used like a mass noun (“vocabulary” in general, not countable items), you mostly encounter the singular form even when talking about “vocabulary” in a broad sense.

Is sentensi singular or plural here, and what noun class does it belong to?

Sentensi is a loanword (from English sentence) and usually behaves like a class 9/10 noun:

Singular: sentensi
Plural: sentensi (same form)

Class 9/10 nouns often look the same in singular and plural. Number is understood from:

Context
Verb and adjective agreement (if shown)
Quantifiers (like moja, chache, nyingi, etc.)

In your sentence:

tunatunga sentensi
Since there’s no moja or plural marker, the context of a classroom activity makes it natural to interpret this as “sentences” (plural), even though the noun itself doesn’t change form.

Examples:

Sentensi moja = one sentence
Sentensi nyingi = many sentences

What exactly does mistari mipya mean, and why is it mipya and not mpya?

Breakdown:

mstari = line / row / verse (class 3, m-/mi-)
mistari = lines / verses (class 4, plural)
mpya / mipya = new

In your sentence:

mistari = lines/verses (plural)
mipya = new (adjective agreeing with plural class 4)

Adjectives in Swahili must agree with the noun’s class and number. The basic adjective -pya (new) changes its prefix:

Class 3 singular: mstari mpya (one new line)
Class 4 plural: mistari mipya (new lines)

So mipya shows:

mi- = plural for class 4
-pya = new

That is why mipya (not mpya) is used after mistari.

What is the difference between kutunga (as in tunatunga sentensi) and kuandika?

Both involve producing language, but they are not the same:

kutunga = to compose, to create (usually something with some artistic or creative element)
Often used for:
- kutunga sentensi = to compose sentences
- kutunga mashairi = to compose poems
- kutunga wimbo = to compose a song
kuandika = to write (physically writing, or writing text)
- kuandika sentensi = to write sentences
- kuandika barua = to write a letter

In this context:

tunatunga sentensi na mistari mipya suggests “we are creatively forming/making up new sentences and lines/verses”, not just copying them down.
If the focus were simply on writing them down, you might see tunaziandika sentensi instead.

So kutunga emphasizes the creative, composing aspect.

Is there any nuance difference between saying Siyo tu leo tunarudia msamiati, bali pia tunatunga sentensi… and something like Leo hatutarudia tu msamiati, bali pia tutatunga sentensi…?

Both are grammatical, but they differ in tense and emphasis.

Siyo tu leo tunarudia msamiati, bali pia tunatunga sentensi…
- Uses present -na- tense for both verbs.
- Feels like: “Not only (are we) reviewing vocabulary today, but we are also composing…”
- Neutral about whether it’s happening right now or planned for today’s lesson.
Leo hatutarudia tu msamiati, bali pia tutatunga sentensi…
- Uses future -ta-: hatutarudia, tutatunga.
- Literally: “Today we will not just review vocabulary, but we will also compose sentences…”
- Sounds more clearly like a plan for later (future today).

The original with Siyo tu … tunarudia … tunatunga … is a more standard, fixed-looking pattern and is very natural in classroom speech when stating what is happening/being done in today’s lesson.

Could this sentence be rephrased in a simpler or more neutral way without losing the main idea?

Yes. You can keep the basic meaning without the emphasized “not only … but also …” structure. For example:

Leo tunarudia msamiati na kutunga sentensi na mistari mipya.
Today we are reviewing vocabulary and composing sentences and new lines.

Or, keeping a softer contrast:

Leo tunarudia msamiati, na pia tunatunga sentensi na mistari mipya.
Today we are reviewing vocabulary, and we are also composing sentences and new lines.

These rephrasings are grammatically simpler, but they lack the stronger emphasis that Siyo tu … bali pia … gives.