What discipline deals with the following questions?

[Avichal]

I've been pondering on questions like:-

What makes certain quotes or statements powerful? Is it just the meaning that it conveys or the choice of words matter?
How our language and choice of words change when we talk about someone we hate or love? There is something called distancing language where we use words to distance ourselves from someone.

Basically its an area overlapping psychology and linguistics. Is there any specific name to it? Any other help appreciated.

 

[brainpushups]

This might not be quite what you mean, but rhetoric is a field that studies the power of language for the sake of argument. This was first discussed in detail by the Sophists and their methods attacked by Plato. There is a work by Aristotle also on the subject.

 

[zoobyshoe]

I think the discipline you're looking for is just writing.

Take a look at this page on word choice from a writing web site:

http://grammar.about.com/od/tz/g/Word-Choice.htm

So, I think the place to look for answers to your questions would be any literature purporting to provide a strategy and tactics for effective writing.

 

[Astronuc]

I've been pondering on questions like:-

What makes certain quotes or statements powerful? Is it just the meaning that it conveys or the choice of words matter?
How our language and choice of words change when we talk about someone we hate or love? There is something called distancing language where we use words to distance ourselves from someone.

Basically its an area overlapping psychology and linguistics. Is there any specific name to it? Any other help appreciated.

Probably psycholinguistics, http://en.wikipedia.org/wiki/Psycholinguistics - note the concern about "needs additional citations for verification".

Semantics is another area of trying to understand the meaning of words and language, but one is interested in the influence, which leads to understanding the effect of language on thought and behavior, which would seem to be addressed in cognitive psychology.

Folks are studying the matter - http://www.mpi.nl/departments/psychology-of-language (Max Planck Institute for Psycholinguistics)

So psycholinguistics seems to be a legitimate term, even if the Wikipedia article is somewhat weak.

 

[zoobyshoe]

Probably psycholinguistics, http://en.wikipedia.org/wiki/Psycholinguistics - note the concern about "needs additional citations for verification".

Semantics is another area of trying to understand the meaning of words and language, but one is interested in the influence, which leads to understanding the effect of language on thought and behavior, which would seem to be addressed in cognitive psychology.

Folks are studying the matter - http://www.mpi.nl/departments/psychology-of-language (Max Planck Institute for Psycholinguistics)

So psycholinguistics seems to be a legitimate term, even if the Wikipedia article is somewhat weak.

Psycholinguistics seems to be about much more basic language abilities than the OP is asking about. It's an approach to the question of why we can have language at all, as opposed to how we produce specific effects with language.