Digraphs can include a combination of consonants or vowels.
The combination 'ay' is a digraph.
The following is from the conversation between Dr. Kathryn Garforth and Jennifer Buckingham.
Sight words or one that has been memorized based on its shape vs the word that has been orthographically mapped. Because I see in many classroom teachers sending home Dolch words and expect kids to memorise them. Let us talk about why that is not the best approach and how memorizing a word is different from mapping it orthographically in your brain (Kathryn Garforth).