Staggered Speech is a tiny onscreen keyboard software, can be used with Camera Mouse or EagleEyes or any other head-controlled or eye-controlled access technology.
Staggered Speech features large buttons with plenty of space between them. First one chooses the group that contains the desired letter and then one chooses the particular letter in that group. Groups begin at the vowels.

The license of this software is Freeware, you can free download and free use this mouse & keyboard software.