Learn Hardcore Swahili: Kama usingekuja leo, ningejisikia upweke sana nyumbani. - If you had not come today, I would feel very lonely at home.

Both usingekuja and ningejisikia use the -nge- conditional form, which covers “would” / “would have” meanings. Swahili uses the same -nge- form for:

present unreal: If X happened, Y would happen.
past unreal: If X had happened, Y would have happened.

So Kama usingekuja leo, ningejisikia upweke sana nyumbani can be understood as:

If you hadn’t come today, I would have felt very lonely at home. (past, counterfactual)
or in some contexts:
If you didn’t come today, I would feel very lonely at home. (hypothetical about today)

Context usually decides whether the speaker means past or present, because -nge- itself doesn’t mark past vs. present.

How is usingekuja built up morphologically, and what does each part mean?

usingekuja can be broken down like this:

u- = you (2nd person singular subject prefix)
-si- (realized here as part of usi-) = negative marker
-nge- = conditional marker (would / would have)
-kuja = verb stem “to come”

So:

ungekuja = you would come / you would have come
usingekuja = you would not come / you would not have come
In our sentence, because of kama “if”, it’s if you hadn’t come / if you didn’t come (today).

How is ningejisikia formed, and what does the ji- part do?

ningejisikia breaks down as:

ni- = I (1st person singular subject prefix)
-nge- = conditional marker (would / would have)
-ji- = reflexive marker (myself)
-sikia = verb stem “to hear / feel / sense”

Literally, kujisikia is like “to feel oneself”. Idiomatically it just means “to feel” (physically or emotionally).

So ningejisikia = “I would feel” (about myself).

Why do we say ningejisikia upweke instead of just ningesikia upweke?

Without ji-, kusikia mainly means “to hear” (sounds, news, information).
With ji- → kujisikia, the meaning shifts to “to feel (in oneself)”.

ningesikia upweke would sound more like I would hear loneliness (which is odd).
ningejisikia upweke = I would feel lonely / I would feel loneliness.

So the reflexive ji- is needed to get the natural “feel (emotionally/physically)” meaning.

What is the difference between upweke and mpweke? Why use upweke here?

Both come from the idea of “aloneness / loneliness,” but:

upweke is a noun = loneliness, solitude (an abstract state or feeling).
mpweke is an adjective / noun class 1 person form = a lonely person, someone who is alone.

In this sentence:

ningejisikia upweke = I would feel loneliness / I would feel lonely (focusing on the feeling as a state).
You could form a different structure with mpweke, e.g.:
ningehisi kuwa mpweke = I would feel (that I am) lonely.

But kujisik(i)a upweke is the more natural, idiomatic way to express “feel lonely.”

Can kama be omitted? Could I just say Usingekuja leo, ningejisikia upweke sana nyumbani?

Yes, kama (“if”) can often be omitted when the -nge- conditional is used, because the -nge- already signals a conditional relationship.

So:

Kama usingekuja leo, ningejisikia upweke sana nyumbani.
Usingekuja leo, ningejisikia upweke sana nyumbani.

Both are acceptable. Including kama just makes the “if” relationship slightly more explicit and is very common in speech and writing.

Why is it upweke sana nyumbani and not upweke nyumbani sana? Where should sana normally go?

sana means “very / a lot” and typically comes right after the word or phrase it is intensifying, often:

right after a verb:
- Nimechoka sana. = I’m very tired.
right after an adjective or abstract noun of quality:
- ana furaha sana. = she’s very happy.

In upweke sana nyumbani:

sana is intensifying upweke (loneliness), not nyumbani (at home).
So the meaning is “very lonely at home”, not “lonely very at home.”

If you said upweke nyumbani sana, it would sound like sana is connected to nyumbani (“very at home”), which is odd or unclear in this context. The usual, natural order is what you see in the sentence.

Does nyumbani need a preposition like kwenye or katika before it?

No, nyumbani already has a locative meaning built into its form:

nyumba = house
nyumbani = at home / in the house

You can say:

Niko nyumbani. = I’m at home.

Using kwenye / katika is possible but usually unnecessary and more formal/heavy here:

katika nyumba = in the house (slightly more literal, physical location)
kwenye nyumba = in/at the house

For the everyday idea of being at home, nyumbani alone is standard and natural.

How would the sentence change if I wanted a positive conditional: “If you came today, I would feel very lonely at home”?

You mainly change the negative conditional in the “if” clause:

Negative: Kama usingekuja leo… = If you didn’t come / If you hadn’t come…
Positive: Kama ungekuja leo… = If you came / If you were to come today…

So:

Kama ungekuja leo, ningejisikia upweke sana nyumbani.
= If you came today, I would feel very lonely at home.

The answer clause still uses -nge-: ningejisikia = I would feel.

How would the verb change if I were talking to more than one person (you plural) instead of just one?

You only change the subject prefix from u- (you sg.) to m- (you pl.):

usingekuja (u-…-nge…): you (sg.) would not come / would not have come
msingekuja (m-…-nge…): you (pl.) would not come / would not have come

So the plural version of the sentence is:

Kama musingekuja leo, ningejisikia upweke sana nyumbani.
= If you (all) hadn’t come today, I would have felt very lonely at home.

Can the word leo (today) move to another position, like Kama leo usingekuja or ningejisikia leo upweke sana nyumbani? Does that change the meaning?

Yes, leo is fairly flexible, and moving it changes emphasis more than basic meaning.

Examples:

Kama usingekuja leo, ningejisikia upweke sana nyumbani.
– neutral, ordinary order; “If you hadn’t come today…”
Kama leo usingekuja, ningejisikia upweke sana nyumbani.
– puts more emphasis on leo, like: “If today you hadn’t come (as opposed to some other day)…”
Kama usingekuja, leo ningejisikia upweke sana nyumbani.
– stresses that the feeling today would be loneliness, e.g. “If you hadn’t come, I would be feeling lonely today at home.”

All are grammatically possible. The version you were given is the most straightforward and common.

Why is the -nge- conditional used in both parts of the sentence and not only in the “if” clause?

In Swahili, for unreal / hypothetical conditions (especially ones that are contrary to fact), it is normal to use -nge- in both clauses:

Kama usingekuja leo, ningejisikia upweke sana nyumbani.
If you hadn’t come today, I would have felt very lonely at home.

Pattern:

If-clause (protasis): subject + (si) + nge + verb
Result clause (apodosis): subject + nge + verb

Using -nge- in both clearly marks this as hypothetical / unreal, much like English “would / would have” in the result clause and sometimes “had / did” in the if-clause.