According to this site's Bulgarian spelling of the name and the site
http://www.omniglot.com/writing/bulgarian.htm, Ivayla is pronounced "ee-vay-lah," and
Ivaylo is pronounced "ee-vay-lo." You kind of have to know IPA for the pronunciations.
"Ekke, Ekke, Ekke, Ekke, Ptang, Zoo Boing!"