The digraph ch represents a velar sound.
The sound of ch is:
ch: schedule, scheme, school.
Ch is a digraph because two letters represent only one sound, in this case, /k/. To articulate it, the tip of the tongue is pressed against the soft palate, forming a barrier that will be broken by the stream of air, producing the sound. This procedure is the same as in letter c, another velar consonant, as both represent the same sound.
- ch is voiceless, so the vocal cords do not vibrate during the articulation.
External link to Sound: CH exercises (1161).