-du [du]
Pronoun[relative]. question marker, attaches to verbs and to relative pronouns such as goo, naa, ndaa, etc
../mp3s/d/-du-vn-hb-06.mp3 Ndaadu dm g̱ooyn? Where are you going?
../mp3s/d/-du2-vn-hb-06.mp3 Goł g̱a̱n sis'aaxsdut Kayla? Why is Kayla laughing?
Goł wils liimi du dm yaatm? What kind of song will we sing?

Related entries: Compare -di2  negative/question marker | sg̱a̱dpduu  size (pl.) | Cross Ref: -u3  indefinite pronoun question marker