Waan vs. Waxaan

Waan cunay hilib lo'aad     - I ate beef
Waxaan cunay hilib lo'aad  -  What I ate was beef


You use 'waan' to make a simple declarative sentence. But. for example, if someone asked you,


Maxaad cuntay? - What did you eat?


you're more likely to answer by saying 'Waxaan ...'. 'Waxa' sort of  means'thing'. So it literally means,

Waxa       aan        cunay       hilib lo'aad
THING    THAT I       ATE                BEEF

Waxaan cunay  - What I ate was
Waxaad cuntay - What you ate was
Wuxuu cunay   - What he ate was
Waxay cuntay  - What she ate was
Waxannu cunnay - What we ate was
Waxeynu cunnay - What we ate was
Waxaad cunteen - What you(pl) ate was
Waxay cuneen - What they ate was