Well language can be expressed many different ways outside of words. Body language, sign language, scents given off, all express emotions and intent. While it's impossible to imagine living any kind of life with even the most animistic forms of expression and communication you'd have to wonder what babies dream of. Of course, since brain development even the newest newborn has had experiences and feedback from the world around him/her to begin learning how to communicate.
To completely isolate someone from birth from any and all interaction with not only humans but animals all together would be interesting to see the effects of. Entirely impractical and inhumane as well. But how could that happen? How could you pull that off? I don't think it's possible.
there's this 1 year old kid whose parents died in jungle..... amazingly, the kid got adopted and raised by a group of apes.
at age 8, the boy was caught by some expeditioners but he acted like a wild beast ( pretty much as today's kids ). 3 months later he was speaking perfect English....