Last night, Zach and Adelie had this "conversation."
Adelie walked into the kitchen, wearing one shoe and holding the other one.
Adelie: "Da!" (while holding her shoe up to Zach)
Zach: "Yes. That's your SHOE."
Adelie: (with a disgusted look, she lifted up her shoe-less foot and signed 'please')
Zach: "Oh, you want your shoe ON?"
(He then proceeded to put her shoe on her foot.)
When both shoes were on, Adelie signed 'thank you', turned, and walked out of the kitchen.
I was pretty impressed, not only with Adelie's ability to communicate (and her manners), but with the fact that a whole conversation took place where one of the participants only said one word that really isn't a word.