Hi, from what information has been provided, it seems like your child has developmental delay. You say that he responds appropriately to television and general human emotions which gives the idea that higher mental functions might be normal. Regarding his speech delay
and inability to walk, if we have to put a single diagnosis, it probably might be due to a congenital disorder in his muscles. So going by the information provided, your child might have a disorder of muscles.
Your kid will need a deatailed evaluation and additional tests to diagnose and treat.
You need to consult a pediatrician
or a pediatric neurologist
. In Delhi you can consult at the pediatric department at AIIMS.
Do keep me posted.