Where's the Yiddish in the Yiddish?

I was in a Jewish library which is frequented by many Yiddish speaking people.  Not for the first time, I heard a mother tell her child to "choosen" a book.  Choosen? You mean kleiben? If you're supposedly speaking Yiddish, why not speak Yiddish!?

Soon after, a child told her mother "ich ken nisht reachen," - she couldn't reach, again, using an English word. 

This is a common phenomenon, most well-known in the child's request, "Ken mich crossen de street?" when they want assistance in crossing the street.

I once said to a parent, you know the proper Yiddish word but since you don't use it, your child does not know it.  Why don't you speak Yiddish if you're speaking Yiddish ... ?

(for related posts, see other listings under the label Yiddish)