The Chinese and English Instructor, compiled by T‘ong Ting-kü and published in Canton in 1862, is an English teaching material that utilized many newly-created Chinese characters to phonetically express the pronunciations of English words which were difficult to express with pre-existing Cantonese sounds. These characters featured an existing glyph and a pseudo radical ‘mouth’ 口, such as, 呷, composed of 甲 and 口. The explanatory notes at the beginning of this book listed many such characters. This study investigates the phonological effects of the addition of this component, focusing on the newly-created characters with the mid front unrounded vowel /e/ as their main vowel. The results showed that the values of certain parts of the syllable changed by regularly adding the pseudo radical ‘mouth’ to the existing glyph. It was observed that besides the vowel shift occurring in the main vowel in almost all groups, tone alternation occurred in most groups as well.