The bound interrogative stem -pi asks “which one?” or “which ones?” when the alternatives are visible, previously mentioned, or otherwise limited. It cannot normally stand bare. A noun-class concord turns it into forms such as yupi, lipi, kipi, ipi, and zipi, so the question itself identifies the kind and number of thing being selected.
English uses unchanged which and then often uses one/ones. Standard Swahili lets concord do both jobs. With an overt noun, the -pi form follows that noun; when the noun is recoverable, the agreeing form can stand independently. All unlabelled uses below are neutral in (informal) speech and (formal) writing.
The most useful forms
The complete paradigm belongs in the agreement table for -pi. This compact map covers the forms most often needed in everyday selection:
| Class | Head | Form | Postnominal phrase |
|---|---|---|---|
| 1 | mgeni | yupi | mgeni yupi |
| 2 | wageni | wepi | wageni wepi |
| 3 | mti | upi | mti upi |
| 4 | miti | ipi | miti ipi |
| 5 | gari | lipi | gari lipi |
| 6 | magari | yapi | magari yapi |
| 7 | kitabu | kipi | kitabu kipi |
| 8 | vitabu | vipi | vitabu vipi |
| 9 | simu | ipi | simu ipi |
| 10 | simu | zipi | simu zipi |
Class 2 has both wepi and wapi. Careful Standard Swahili can use wepi to avoid a clash with the ordinary question wapi “where,” although wapi remains established and is common in current speech. Human nouns follow semantic class 1/2 agreement: daktari yupi and madaktari wepi/wapi, even though their noun shapes do not show m-/wa-.
The locative-class forms papi (class 16), kupi (class 17), and mpi (class 18) are possible when an understood set of places is itself being classified or contrasted, but they are uncommon in ordinary conversation. Everyday “where?” is normally the invariant adverb wapi. Recognize the locative -pi forms in careful grammatical or (formal) usage rather than treating them as routine substitutes for wapi.
Mgeni yupi atasaini fomu hii kwanza?
Which guest will sign this form first?
Gari lipi litawachukua wageni hadi hotelini?
Which car will take the guests to the hotel?
Vitabu vipi vinahitajika kwa somo la kesho?
Which books are needed for tomorrow's lesson?
The verb continues the same controller: class 1 yupi—a-, class 5 lipi—li-, and class 8 vipi—vi-.
Put -pi after an overt noun
Swahili neutral noun-phrase order is noun + agreeing -pi form. The entire phrase remains where an ordinary noun phrase would stand; it does not have to move to the front as English which + noun normally does.
Ulichagua kozi ipi kwa muhula wa pili?
Which course did you choose for the second term?
Tutatumia jengo lipi kwa mafunzo ya Jumamosi?
Which building will we use for Saturday's training?
Walipanda miti ipi kando ya barabara?
Which trees did they plant beside the road?
In u-li-chagu-a, u- marks singular “you” and -li- marks past time. The question form ipi is a separate class 9 modifier after kozi; it is not a verb suffix. Finished finite verbs are written solid: ulichagua, never u li chagua.
Independent -pi means “which one(s)?”
Once the choice set is clear, omit the repeated noun but keep the concord form. The class and number of the omitted head remain active.
Nimeleta mashati manne; utavaa lipi kwenye sherehe?
I brought four shirts; which one will you wear to the celebration?
The set contains plural class 6 mashati, but the answer will be one singular class 5 shati, so the independent selection is lipi. To choose several shirts, ask utavaa yapi?
Simu zote ziko mezani; ipi ina kamera bora?
All the phones are on the table; which one has the better camera?
Nyaraka zimepangwa katika mafungu matatu; zipi zinahitaji sahihi?
The documents have been arranged in three piles; which ones need a signature?
Independent ipi controls singular class 9 i- in ina; zipi controls plural class 10 zi- in zinahitaji. There is no invariant free word for English “it” or “they.” Once the answer is known, class concord continues it:
Ipi ina kamera bora? Ile imechajiwa leo.
Which one has the better camera? The one over there was charged today.
Both ipi and ile recover a singular class 9 simu.
-pi versus gani and nani
Gani is invariable and commonly asks for an open identity, description, or type. -Pi strongly presents a bounded choice. The distinction is about the discourse set, not merely the English translation.
Unapenda muziki gani?
What kind of music do you like?
Kati ya nyimbo hizi tatu, unapenda upi zaidi?
Of these three songs, which one do you like most?
Unataka kahawa gani?
What kind of coffee do you want?
Kati ya vikombe hivi, unataka kipi?
Of these cups, which one do you want?
In everyday (informal) speech, gani often overlaps with English “which.” Use -pi when the known set matters or when “which one(s)” is the intended contrast. Nani asks an open human identity and replaces the noun phrase: Nani amepiga simu? “Who called?” By contrast, mfanyakazi yupi? asks which employee from an understood group.
Pro-drop and emphatic personal pronouns
The subject marker normally identifies the speaker or listener without a free pronoun:
Utachagua lipi kwa safari ya kesho?
Which one will you choose for tomorrow's trip?
Add independent pronouns only to contrast participants:
Wewe utachagua lipi, na mimi nichukue lipi?
Which one will you choose, and which one should I take?
The first is neutral pro-drop. In the second, wewe contrasts with mimi, while the verbs still contain subject marking: u-ta-chagu-a and first-person subjunctive ni-chuku-e. The independent words do not replace those verb slots.
Common Mistakes
Putting -pi before its noun like English “which”
❌ Kipi kitabu utatumia darasani?
Incorrect neutral order — the agreeing interrogative follows its overt noun.
✅ Utatumia kitabu kipi darasani?
Which book will you use in class?
Using ipi for every nonhuman class
❌ Kati ya magari haya, utatumia ipi?
Incorrect — the selected noun is singular class 5 gari, so use lipi.
✅ Kati ya magari haya, utatumia lipi?
Which of these cars will you use?
Using -pi for an open question about type
❌ Unasoma muziki upi?
Incorrect for the intended open question about musical style.
✅ Unasoma muziki gani katika kozi hiyo?
What kind of music do you study in that course?
Repeating an English-style subject pronoun without contrast
❌ Wewe utachukua kiti kipi?
Overemphatic if only one listener is being asked and no contrast is intended.
✅ Utachukua kiti kipi?
Which chair will you take?
Using wao as “they” for class 10 objects
❌ Nyaraka zipi zimefika, na wao ziko wapi?
Incorrect — wao is a human plural pronoun, not a general word for class 10 ‘they.’
✅ Nyaraka zipi zimefika, na ziko wapi?
Which documents have arrived, and where are they?
Key Takeaways
Use -pi to select from a recoverable set. With an overt noun, put the agreeing form after it; without the noun, let the form stand for “which one(s)” and keep the selected noun's class and number. Use gani for a more open identity or type question, keep personal subject reference inside the finite verb, and add independent pronouns only when participant contrast matters.
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Start learning Swahili →Related Topics
- nani and nini: Who and WhatA1 — Ask who and what with invariant nani and nini in subject, object, and copular questions without importing English question word order.
- Indefinite Pronouns with -ote and -o-oteB1 — Build class-agreeing forms such as yeyote, chochote, and popote for anyone, anything, and anywhere.
- Agreement with -pi 'Which?'B1 — How the interrogative stem -pi agrees with every Swahili noun class and selects one or more members of a known set.
- Pronominal Concords for Noun ClassesB1 — Refer to omitted nouns through class-agreeing demonstratives, possessives, -ote forms, -enye phrases, and markers inside the verb.