The colloquial verb “kam2” 冚 seems to be more commonly used than the corresponding “kap1” 扱, both meaning ‘to cover on top’.
Most linguists believe that the syllables with nasal codas are the more basic originals while the stops are the colloquial variants.
Other linguists regard the alternation between homorganic final consonants in pairs of semantically-related words as a feature widely found among languages of Southeast Asia as well as south China (Chuang-chia and Hmong for example).
[4] Similarly, Bauer notes that the Cantonese phenomenon is believed to be a remnant of an ancient word-derivation process, now no longer productive, in which different types of suffixes (causative and transitive) were attached to lexical roots.
[5] In the Cantonese syllabary, there are about 50 pairs of such characters that show alternation between homorganic nasal and stop codas.