dialectology
noun
di·a·lec·tol·o·gy ˌdī-ə-ˌlek-ˈtä-lə-jē 
1
: the systematic study of dialect
2
: the body of data available for study of a dialect
dialectological
ˌdī-ə-ˌlek-tə-ˈlä-ji-kəl
adjective dialectologically
ˌdī-ə-ˌlek-tə-ˈlä-ji-k(ə-)lē
adverb 
Word History
Etymology
International Scientific Vocabulary
First Known Use
1820, in the meaning defined at sense 1