I personally know 5 adult yorkies (owned by friends of mine) and of course, my adult is Diva. NONE of the dogs that I know are yappy. Diva rarely ever barks, unless there is a knock at the door or the evil
cat gets in trouble for something and Diva has to back me up by barking like crazy at her!
Honestly, the only thing I could say bad about a yorkie is that they may cause diabetes because they are so freakin sweet!!! (my 18 year old daughter told me that and I loved it!)
Don't let anyone talk you out of getting what you want.