Wino

I was asking Cal about letter sounds in the car today. "What word starts with the same sound as the word "snow?" He said, "S." I explained to him what I meant (e.g. snake, sun, etc) and tried again.

Me: What word starts with the same word as "white."
Cal: W.
Me: No. What has the same SOUND as the first sound of "white."
Cal: D.
Me: Wha...?
Cal: W starts with the letter "D." (Double U)
Me: Oh. Well... that's true. But what word starts with a "W" like the word "white."
Cal: Wine. Like the wine that you drink. But not kids. Just grown-ups. Why can't I drink wine?