omitting-es, s in the Present Simple

I like watching films,in English,of course,and Ive noticed something.They sometimes dont use es,or s in their conversation.For examp-He go instead -goes,m in the Pres Simple, is it possible?Can we omit es,s?Why?

It is not possible. Perhaps those characters were speaking in dialect. Film is not a shining example of proper English. The best films capture the real world, and in order to do so, they vary the education level and formality of characters.

Perhaps,I`m sure that I hear very well,but I know it is impossible.Thanks a lot,Mordant
p.s. I studied,and finished of course,english language at the University and I have some more questions