Statistically, verbal abuse often preceeds physical violence. I also speak from experience and it is true that abusers are likely not to change because they have no incentive to, as long as their tactics work towards getting them what they want.
The advice on the forum in right, proving verbal abuse is difficult and I can understand where your concerns lie. Alienating a normal person with whom your marriage has not worked is not the same thing as dealing with an abuser who is likelier than most to use anything, especially children to cause you hurt and trouble and even use the children as a means to keep tabs on you, manipulate you and threaten to take them away from you to keep you from leaving, with utter disregard to the damage such behavior causes the children. An abuser often holds their loved ones to horrendous standards and children are not spared. It is an unfair fight to begin with.
At the same time, the courts in India will not see this the same way and in that, the learned members here know more than I do.
I hope you can find the kind of lawyer who understands the aspects of verbal abuse amounting to mental cruelty and has established themselves as someone who can take the right view of things. Your best bet would be to look for a lawyer who can truly understand the nuances of such a situation and build your case accordingly.
This will be a hard fight, he won't be willing to let you go as easily because abusers need someone to abuse and your leaving will prompt tears, begging and promises of change etc. The honeymoon period will end and the abuse cycle will restart, with time the honeymoon period will grow shorter and the periods of abuse, alienation and degrading you will lengthen. Keeping a child in this scenario would mean the child will bear witness and also likely be subjected to abuse and grow up with an unhealthy view of relationships and the world.
If you are open, I would suggest that you seek counselling for overcoming the resulting trauma from the abuse. Also, should the courts grant your husband visitation, please monitor your child carefully and see if they show any signs of being treated badly or being assaulted verbally. A counsellor will be able to help you understand these signs.
Right now, though, I think you are doing the right thing by moving away from your husband. Your child deserves to grow up in a healthy and abuse-free environment.