Schaff, Philip. "Ch. 25: The Style and Vocabulary of the Didache." The Oldest Church Manual Called the Teaching of the Twelve Apostles. Second Edition, Revised and Enlarged. New York: Funk & Wagnalls, 1886, 195-113.
Schaff observes that the Didache is in Hellenistic Greek, similar to the Greek of the New Testament (Schaff 1886, 95). The use of Hebraisms and the lack of technical language which emerged in the patristic writings points to an early date (Schaff 1886, 96). Much of the vocabulary is identical to that of the Synoptic Gospels. "The Didache contains 2,190 words. Its vocabulary comprises 552 words. Of the whole number 504 are New Testament words, 497 are classical, and 497 occur in the LXX. 16 occur for the first time in the Didache, but are found in later writers. 1 occurs only in the Didache. 14 occur in the New Testament with a different meaning" (Schaff 1886, 97). Schaff goes on to provide lists of words in the various categories (Schaff 1886, 99ff).