Many people in this country who graduate college have language skill performance on about the 10th grade level. We just keep lowering the bar.

I know people who taught "survival classes" for the YWCA. They taught adults to find job listings in the classified ads, fill out job applications, balance a checkbook, etc. Many of the students were "first generation literate". They grew up in families with no literate members and never learned to value reading skills.

People who use the same words but to represent different meanings cannot learn from each other. The value of learning different languages is not controversial in any way.

I am impressed that your nephew has not figured out how to print graphs of market information from the internet. Maybe it is a family thing and explains your lack of understanding of the significance of a baby learning sign language at an age when they don't even recognize themselves in a mirror. Babies don't recognize themselves in a mirror until they are nearly two years old, four for some. The idea that they can recognize others and recognize symbolic communication is quite impressive.