Azizah, N. and Sudiran, S. 2017. A Study on Diglossia Used by Helen Keller as The Main Character in George Sullivan’s Novel "Helen Keller". Celtic : A Journal of Culture, English Language Teaching, Literature and Linguistics. 2, 1 (Aug. 2017), 1–18. DOI:https://doi.org/10.22219/celtic.v2i1.4672.