To form questions that elicit yes/no reponses, place the particle "ka" or "kad" at the beginning of a sentence.

  • Ka Sean iris a la skolo? Did Sean go to school?
  • Kad el perdis la pekunio? Did she lose the money?

Simple questions may be formed by placing "Ka" in front of a noun without a verb. Ka Michelle? can mean "Is it Michelle?" or "Do you mean Michelle?", depending on the context.

If there is a word like who, what, where, etc., ka/kad is not used:

  • Ube vu habitas? Where do you live?
  • Quo es filozofio? What is philosophy?
  • Quon vu timas? What do you fear?
  • Qua es la prezidanto? Who is the president?
  • Quante vu evas? How old are you?