Grandma's WHAT?

It's becoming ever-clearer that I have to mind my words with much more caution than ever before. With a fledgling English-speaker in the house, word pronunciation and diction are becoming more and more important. Take for instance our little "misunderstanding" on the way home from the babysitter's on Wednesday. I mentioned my mom in conversation to David and from the back seat, Zach begins to yell that he wants to talk to Maw Maw NOW!! He loves, loves, loves to talk on the phone and who am I to deprive him, so I told him I'd call her...the rest of the conversation went like this:

Me (under my breath to David): I wonder if he'd protest if we just called Granma (his mother) instead?
David: not sure what David said because I got an earful from backseater;
Zachary: Granma's DEAD?
Me: WHAT? How did you get that?
Zachary: She not dead?
Me: NOOO, granma's very much alive.
David: no words just laughing profusely inside his mouth, lips tightly closed so it sounded quite evil.
Me: Umm, I said inSTEAD honey, not DEAD!!
Zachary: Her dead, granma not dead?
Me: NO, we'll call her in a second so you can ask her.

David's mom got a big kick out of it and assured him that she was very alive. Whew!