At the scene were the Griswalds get at Eddie's house Clark asks a little girl how old she is. Eddie says she was born without tongue, but if you look seconds before that you can clearly see her mouth is open and her tongue is sticking out.
The term "born without a tongue" is an old phrase with means that the person cannot speak (ie: also called "dumb" in the pre politically correct world).
The term does NOT mean that the person was physically born without a tongue, only that they do not speak.