The letters ch and j represent post alveolar affricates voiceless and voiced, whereas the letters sh represent a post alveolar fricative consonant, voiceless.
The affricate sounds are:
ch: cheese, chess, chore;
J: joy, jumper, jungle;
sh: shark, shave, shelf.
Affricates are consonants produced through two consecutive manners of articulation, it begins with a full occlusion of the vocal tract and ends with the release of the collected air through a constricted opening that creates the effect of friction.
When pronouncing ch the tip of the tongue is advanced forward against the palate, whereas, when pronouncing the sound j the tip of the tongue rests back against the palate, forming an obstruction.
- ch: voiceless, vocal cords do not vibrate during the articulation of the consonant;
- j: voiced, vocal cords vibrate during the articulation of the consonant;
To pronounce sh, the tip of the tongue is raised to the alveoli. The front part of the tongue is close to the beginning of the hard palate, forming a gap. The middle part of the back of the tongue is concave, the whole tongue has the shape of a spoon, the lips move forward a little and are rounded. The flow of air, passing through two slits, forms a sound.
- sh: voiceless, vocal cords do not vibrate during the articulation of the consonant.