demoticist
/dɪˈmɒtɪsɪst/noun
1A person who uses, or advocates the use of, vernacular language or ordinary colloquial speech; specifically an advocate of using demotic Greek in writing as well as in speech and in formal contexts as well as informal.
2 Egyptian History (originally and chiefly US ). Usually with capital initial. = Demotist.
Origin
Early 20th century. From demotic + -ist, after modern Greek δημοτικιστής.