Learn Hardcore Swahili: Tunapaswa kulipa ushuru sokoni.

tu- = we (subject marker)
-na- = present/habitual tense
-paswa = be required/obliged/expected (passive of -pasa, “to be fitting/necessary”) So tu-na-paswa = we are required/are supposed to.

Why is kulipa used after tunapaswa instead of tulipe?

After -paswa, the verb that follows is normally in the infinitive form ku- + verb: tunapaswa kulipa. Using the subjunctive (tulipe) here is not the standard pattern.

Compare other obligation patterns:
- Ni lazima tulipe...
- Inabidi tulipe...
- Tunatakiwa kulipa... (often takes the infinitive like -paswa)

What exactly does sokoni mean, and what does the -ni do?

The suffix -ni marks a locative (place). Sokoni means “at/in the market,” and depending on context it can also mean motion “to the market.” The precise sense (at/in vs. to) is inferred from the verb and context.

Could I say kwenye soko or katika soko instead of sokoni?

Yes:

sokoni is the most idiomatic, compact way to say “at/in the market.”
kwenye soko and katika soko are also correct; they are a bit more explicit and sometimes slightly more formal or literal. For many common places, -ni is preferred: shuleni (at school), kanisani (at church), nyumbani (at home), kazini (at work).

What noun class is soko, and what is its plural?

soko is class 5.
Its plural is masoko (class 6).
With the locative, you can get sokoni (at the market) and masokoni (at the markets).

What about ushuru—what noun class is it, and are there synonyms?

ushuru is typically a mass noun in class 14 (sometimes treated like class 11/14). It usually has no plural.
Nuances:
- ushuru = tax/duty/levy (often things like customs duty or market levy).
- kodi = rent; also used in compounds for taxes, e.g., kodi ya mapato (income tax).
- ada = fee/dues (e.g., school fees).
- tozo = charge/levy (administrative fee). Choose based on the kind of payment you mean.

How do I say who the tax is paid to?

Use a recipient with a noun or kwa:

kulipa [mtu/taasisi] ushuru: pay [person/institution] the tax.
kulipa ushuru kwa [mtu/taasisi]: pay tax to [person/institution]. Example patterns: kulipa halmashauri ushuru, or kulipa ushuru kwa halmashauri.

How do I include an object marker to mean “pay it”?

Attach the object marker to the infinitive verb:

If “it” refers to a class 14/11 noun like ushuru, the object marker is u-.
ku-u-lipa usually written as kuulipa: tunapaswa kuulipa sokoni = we should pay it at the market. With people (class 1), you get kumlipa (“to pay him/her”).

How do I negate the sentence?

Use the negative present and change final -a to -i in -paswa:

Hatupaswi kulipa ushuru sokoni. Breakdown: ha- (neg), -tu- (we), verb stem -pasw-, negative ending -i → paswi.

How do I turn it into a yes/no question?

Add Je at the start: Je, tunapaswa kulipa ushuru sokoni?
Or keep the same order and use questioning intonation in speech: Tunapaswa kulipa ushuru sokoni?

Can I move sokoni earlier in the sentence?

You can, for emphasis or style, but the neutral default is to place location at the end. For strong topicalization you could front it: Sokoni, tunapaswa kulipa ushuru, but that adds emphasis and is less neutral.

Can I drop the ku- and say tunapaswa lipa?

No. After -paswa, the following verb should be in the infinitive, which requires ku-: kulipa. Dropping ku- is ungrammatical here.

Is -paswa a normal verb or a modal? Are there impersonal options?

It’s a normal verb (passive of -pasa) that behaves like a modal of obligation. You can use impersonal forms:

Inapasa kulipa ushuru sokoni.
More formal/literary: Yapasa kulipa ushuru sokoni. These mean “it is necessary/required to…,” without specifying the subject.

How strong is the obligation in tunapaswa compared to other options?

tunapaswa: we are supposed/required to (normative/official expectation).
ni lazima tulipe / inalazimu tulipe: stronger, closer to “must.”
inabidi tulipe: practical necessity (“have to”).
tunatakiwa kulipa: similar to tunapaswa, often used in rules/instructions.