So... I wanted to share some wonderful news.
I have recently realized, mostly today, that William is saying a word without any prompting.
Yup! He says "gaah-geee" which is his way of saying "daddy" --- the "d" sound is difficult for him because it requires specific tongue placement.
He was messing with my phone and on the main screen I have some favorite contacts. Ryan's is the main one and it shows his picture. Will brought me my phone, showed me Ryan's picture and kept saying "gaah-geee" and then promptly called him.
Later, Ryan could be heard coming in the house and Will ran to the door saying "gaah-geee" over and over.
BIG MAMMA SMILES! I think he's beginning to really get it!