Consider the words sink, blunt, frank, single, uncle and wind; all of which contain the phoneme /n/. Note that lint, blunt and wind differ from the others in the pronunciation of /n/. Sink, frank, single, and uncle all contain an /n/ folowed by a voiceless /k/ and herein lies the difference. It appears that when an /n/ and a /k/ appear together, nasal assimilation occurs, changing the alveolar nasal /n/ to the velar nasal /ŋ/.