Wrong. Most evolutionary changes are in fact neutral. Also, "the thing will be improved" isn't scientific. Reproductive success of one's self and those related to you are the only thing that matters. In this case, a late puberty doesn't seem to effect the reproductive success of the men in question. Often, delayed or premature puberty is a major trait that changes in species as they adapt to new conditions.
You are implying as if they communicate with each other in sign language , if please provide some site .
Are you not aware of Google? http://articles.orlandosentinel.com/1985-07-07/news/0310230280_1_loulis-chimp-washoe Notice the date on this - old news...
Greater, Than you for enlighten me , Now , I have some question it was a great project Was there any success. The publication is about 30 years ago, I assume there would be more success story any more publication ?