Thalia is a name that has had several different pronunciations in English. People in the USA old enough to remember a television program called
The Many Loves of Dobie Gillis will remember that a character with that name pronounced it THAYL-yuh on that show. THAYL-ee-uh and Thah-LIE-uh have also been used in English speaking countries. And in the USA today the name is often pronounced TAHL-ee-ah under the influence of the pronunciation of the many Hispanic women who bear it.