or·tho·e·py 
(ôr-th
ōə-p
ē, ôr
th
ō-
ĕp
′ē)
n.1. a. The study of the pronunciation of words.
b. The study of the relationship between the pronunciation of words and their orthography.
2. The customary pronunciation of words.
[Greek orthoepeia, correctness of diction : ortho-, ortho- + epos, epe-, word; see wekw- in the Appendix of Indo-European roots.]
or′tho·epic (-ĕpĭk), or′tho·epi·cal (-ĕpĭ-kəl) adj.