A section at the end of the text, called
Ŏnmun chamo ( The text is considered to be of significant interest to modern linguists for a number of reasons. It is the earliest known direct attestation to
names for the letters of Hangul; letter names in current use are based on the ones found here. However, it is unclear if Ch'oe coined the letter names himself. Many possibly incorrectly believe that Ch'oe coined the names. However, that is not clear from the text. Ch'oe states elsewhere in the work that his intent was to document current practice at the time. In addition, the text documented actual pronunciations of the time instead of attempting to enforce artificial prescriptivist pronunciations, which aids linguists in trying to understand authentic contemporary
phonology. The oldest known copy of the text, produced in 1527, is held in Japan. == References ==