Note: Used principally by men; the women’s equivalent of ka na is kashira (#58).
1. Indicates uncertainly: “I wonder.”
Kachō, nanji ni kuru ka na.
What time’s the section chief coming, I wonder.
Taga-kun wa, kono shigoto dekiru ka na.
I wonder if Taga can do this job. / Could Taga handle this job? I wonder.
2. Indicates a question to oneself: “I wonder.”
Kyō wa nan-yōbi datta ka na.
Hmm, what day is today?
Tanaka-san to au no wa nanji datta ka na.
Now, what time was is that I was going to meet Tanaka?
3. Indicates a hope or muted request: “I wonder.”
Kono shigoto, tanonde ii ka na.
I wonder if I could ask [you to do] this job. /Can I ask you to take care of this work?
Ashita no asa hayaku kaisha ni kite moraeru ka na.
I wonder if you could come to the office early tomorrow morning. /Could you come to the office early tomorrow morning.