Is it an established or newly planted Hosta?
Planted in-ground or a pot?
Recently moved to a new location?
Has any landscaping around it been recently changed to allow more sun than it was getting?
Maybe sunburn?
Here are a couple of pics of Hosta that suffered dryness, and were in shade all day. The drying leaves dried from the tips and progressed toward the stem- fairly consistently across several potted plants.
( I was on vacation!)
Your hosta leaves have a more irregular/variable damage pattern, like strong sun the plant wasn't accustomed to experiencing.
Are they on the mend, or still declining?