Dear Kalpesh Jain,
You're requesting so much information on normal development that I really couldn't begin to reply sensibly in this Q & A format. However, I can refer you to a wonderful series of books on normal child development, written by the staff at the respected Gessell Institute in New York. The books are available in titles like: Your Two-Year-Old, Your Three-Year-Old, etc. Also, you might check The Early Childhood Years: The Two to Six Year Old, prepared by the Princeton Center for Infancy and Early Childhood.
Dr. KDK
My 4 years old daughter speaks very little, only single words with her own way of pronunciation. Her comprehension is low, and generally she's delayed, although well independent (toilet, food). She gets some treatment but it doesn't seem to help much. Is there a chance that she will speak? we almost lost our hope. I must add that she's a lovely girl, smart, shows a great interest in music, communicates well, but not by words.