I read or heard somewhere that dogs have about a 150 word vocabulary. I think Yorkies must even exceed that...
I am convinced that ours only cocks her head while she's learning a new word...after that she seems to retain the thought/word even to the extent of me naming her toys. In other words when I tell her to go get Henrietta, she "gallops" up to her litte hippo toy. She just amazes me with how intelligent she is...LOL...but of course I'm not at all prejudiced...LOL