Learn Hardcore Swahili: Kabla ya chakula cha mchana, tunapanga viti vyote sawasawa katika chumba cha kulia chakula. - Before lunch, we arrange all the chairs evenly in the dining room.

Ya is the preposition of (also a connector) that turns kabla into “before [something]”. So kabla ya chakula cha mchana literally is like “before of the midday food” → “before lunch”.

Why is it chakula cha mchana and not something like chakula ya mchana?

Chakula (food/meal) is in noun class 7 (ki-/vi- class in the singular is ki-/chi-/cha-).
Possessive/“of” agreements for class 7 use cha, not ya.

So:

chakula cha mchana = food of daytime → lunch
chakula cha jioni = evening meal, supper

Ya is used with other noun classes (e.g. class 9/10: chai ya asubuhi = morning tea). Here, because chakula is class 7, we must use cha.

How is tunapanga formed, and what tense/aspect is it?

Tunapanga breaks down like this:

tu- = we (subject marker)
-na- = present tense marker (general present / present continuous)
-panga = verb stem “to arrange / to organize / to plan”

So tunapanga means “we arrange” / “we are arranging”.
In this sentence it describes a regular or typical action done before lunch.

Does panga always mean “plan”, or can it also mean “arrange” physically, like here?

Panga is quite flexible:

panga = to arrange, to set in order, to organize, to plan

In this sentence, tunapanga viti vyote clearly means “we arrange all the chairs” (physically putting them in place).
In other contexts, kupanga can be more abstract, like kupanga ratiba (to plan a schedule).

Why is it viti vyote and not viti zote or viti zote zote?

Viti (chairs) is the plural of kiti and belongs to noun class 8 (vi-/v- in the plural).
Adjectives and quantifiers have to agree in class with the noun.

For class 8 (viti), -ote (all) takes the form vyote:
- kiti kimoja = one chair
- viti vyote = all (the) chairs

Zote would agree with class 10 or class 8 nouns that use zi- (e.g. meza zote = all the tables). Since viti uses the vi-/v- pattern, we use vyote.

What exactly does sawasawa mean, and how is it used?

Sawasawa is an adverb/adjectival form from sawa and generally means:

evenly, equally, neatly, properly, symmetrically

In this sentence, tunapanga viti vyote sawasawa means “we arrange all the chairs evenly/neatly (in order)”.

You can use sawasawa after a verb:

Wamepanga vitabu sawasawa. = They have arranged the books neatly/evenly.

It can also be used for “exactly / the same” in some comparisons, especially sawasawa na = “exactly like”.

Why use katika in katika chumba cha kulia chakula? Could I use kwenye or -ni instead?

Katika is a common preposition meaning in / inside / within:

katika chumba = in the room
katika nyumba = in the house

Yes, in everyday speech you can often also use:

kwenye chumba cha kulia chakula
chumbani (using the locative suffix -ni: chumba → chumbani)

So, all of these are possible and natural, with slightly different styles/registers:

katika chumba cha kulia chakula
kwenye chumba cha kulia chakula
chumbani cha kulia chakula (less common, but structurally possible)

Here katika is just a neutral, standard choice.

How is chumba cha kulia chakula built up, and what does each word contribute?

Breakdown:

chumba = room
cha = of (agreeing with chumba, class 7)
kulia = to eat (in this fixed phrase; see next question)
chakula = food

So chumba cha kulia chakula literally is:

“room of eating food” → dining room

It’s a descriptive noun phrase: “the room for eating food”.

I thought kulia means “to cry”. Why is it used here for “to eat” in chumba cha kulia chakula?

You’re right that kulia very commonly means to cry.
However, in certain fixed expressions, especially with chakula, kulia is also used in the sense of “to eat (a meal)”.

So:

kulia chakula in this phrase is understood as “to eat food”.
chumba cha kulia (chakula) is a conventional expression for dining room.

In modern usage, many people also just say kula for “to eat”:

kula chakula = to eat food

You can think of chumba cha kulia (chakula) as a somewhat fixed, traditional expression that learners just memorize as “dining room”.

Can I drop chakula and just say chumba cha kulia for “dining room”?

Yes. Chumba cha kulia on its own is widely understood to mean “dining room”.
Adding chakula:

chumba cha kulia chakula

is a bit more explicit, literally “room for eating food”, but in practice both forms mean dining room and are used.

Does the time phrase Kabla ya chakula cha mchana have to come at the beginning, or could it go later in the sentence?

It can be moved. For example:

Tunapanga viti vyote sawasawa katika chumba cha kulia chakula kabla ya chakula cha mchana.

This is still correct and means the same thing.
Placing Kabla ya chakula cha mchana at the beginning just emphasizes the time setting (“Before lunch, …”) and matches a common Swahili pattern of starting with time or place expressions.

Should there be an object prefix for viti in tunapanga viti vyote? Could I say tunavipanga viti vyote?

In neutral, simple sentences with a full object noun present, Swahili often omits the object prefix:

Tunapanga viti vyote. = We arrange all the chairs.

Adding the object prefix:

Tunavipanga viti vyote.

is grammatically possible but usually sounds redundant or emphatic, e.g. if you’re stressing those chairs in particular.
In normal, straightforward description, tunapanga viti vyote without -vi- is the most natural choice here.