Well, the tone of the rest of the dialog can make it formal or informal.

very formal : " How are you on this fine day, sir?"

formal: "Hello, how are you?"

Somewhat informal "hey, how are you?"

casual:  'what's up with you, man?"

so we don't really need various forms of the same pronoun.

Once upon a time in English was ward thou which means ты but course of time it was forgot. 
William Shakespeare wrore: 
Have more than thou showest
Speak less than thou knowest 

well yeah  i started learn russian language and found very different things

you know like  in russian language as well in Hindi (indian) language  we say  "tu" or tum  in informal  way  and  "aap" in formal way.  

And one more thing here people dont call the father's name in the end of any person's name like in russian  do :) 

and yeah in english we just  "you"  in informal or in formal  way , so i think its good  :)

In English "you" is formal and informal, in Spanish "tú" is informal and "usted" is formal.

Yes, Alice, in English we have only one 'you', but it's the rest of language you use and and how it's said that makes if formal, informal, respectful or otherwise.