In auto-ispell-mode SPC or RET automatically trigger
ispell-word on previously typed word. M-TAB will
make an ispell completion.
Enter and leave with M-x auto-ispell-mode.
Command: auto-ispell-mode
(M-x auto-ispell-mode) Toggle auto-ispell-mode.
With prefix arg, turn auto-ispell-mode on iff arg is positive.
In auto-ispell-mode, inserting a space or a new line applies
ispell-word on the previous word.
Pressing Esc-Tab activates ispell-complete-word.