What do you call letter pairs that make special sounds such as ch, sh, wh, ph?

Question

I have no idea how to search for something like this on the net lol. I know it sounds crazy, call me old if u want lol.I really need to know the name of this section in english language arts, can anyone help me out?

Answer 1

Digraph

Answer 2

Suffix? I think...or root word?..

Answer 3

They are called consonant digraphs in phonics.  Two letters make one sound.

http://www.firstschoolyears.com/literacy...

Answer 4

blends.

good luck