Auxiliary verb
Interjection
Particle
1. (I) will; (I) shall
on non-五段 stem, e.g. 食べる→食べよう; indicates intention
2. let's
on non-五段 stem; indicates suggestion or invitation
3. (I) wonder (if); might it be (that); maybe; perhaps; perchance
on non-五段 stem; indicates speculation