or·tho·e·py 
(ôr-thōə-pē, ôrthō-ĕp′ē)
(ôr-thōə-pē, ôrthō-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.