Robert Priebsch, 1911 Encyclopædia Britannica (1911)
“ Before considering the development of the language spoken within these boundaries, a word of explanation is perhaps necessary with regard to the word deutsch. As applied to the language, deutsch first appears in the Latin form theotiscus, lingua theotisca, teutisca, in certain Latin writings of the 8th and 9th centuries, whereas the original Old High German word thiudisc, tiutisc (from thiot, diot, “people,” and the suffix -isc) signified only “appertaining to the people,” “in the manner of the people.” ”
