47.What do the sounds in ai (as in rain), ay (as in day), ea (as in teach), and ea (as in bread) refer to?
(A) Vowel Digraph.
(B) Homophones.
(C) Blends.
(D) Diphthongs.

A digraph is two letters that spell one sound. Digraphs that spell consonant sounds include the letter pairs sh, ch, th, wh, ck, ph, ng. Digraphs that spell vowel sounds include the letter pairs ai, ay, ee, ea, ie, ei, oo, ou. ow, oe, oo, ue, ey, ay, oy, oi, au, aw. The important thing to remember is that a digraph is made of two letters, and although the letters spell a sound, the digraph is the two letters, not the sound.

A diphthong is a special kind of vowel sound. Most vowel sounds in English are made with the mouth in one position and with one pure sound. These vowel sounds are called monophthongs (mono meaning “one” and phthongmeaning “sound”). A diphthong is one vowel sound formed by the combination of two vowel sounds. A diphthong begins as one vowel sound and moves toward another, such as the vowel sounds in coin or loud. Diphthongs can be contrasted with two monophthong vowel sounds together that form two syllables, such as in chaos, triage, or violin.1