What do these messages say?

Hint: all of these are using a=1

8-9! 8-15-23 1-18-5 25-15-21 4-15-9-14-7 20-15-4-1-25?

23-8-9-3-8 9-19 2-5-20-20-5-18, 3-1-20-19 15-18 4-15-7-19?

9 11-15-22-5 20-8-5 3-15-12-15-18 20-5-1-12.

Answers!