On B.L. Whorf, visit:

• http://grail.cba.csuohio.edu/~somos/whorf.html
  
  
  On J. Piaget, visit:
  

• http://www.piaget.org/
  
  
  Steven Pinker’s books on the subject include:
  Language Learnability & Language Development
  How the Mind Works
  The Language Instinct