~Language in itself is simply a mental activity, rather a process to organise and far vitally to convey our perception to others. As an unit of consciousness most of the language would be a flux of personal broken thoughts and feelings. But I think what you are asking me is language as an identity and its relevance to day to day prejudice.
Language though is a learnt system forms one of the core attributes of identity not just in itself but also as an important mirror of socio-cultural values. And more often language becomes a token of prejudices against the latter values. In itself, languages are mutually exclusive and do not foster any negative emotion.
In cultures where language is one of the prime facets of identity, by which I mean circles where in meaningful intercultural exchanges has yet to begin or has just started, language forms a easy symbol for exhibiting any associated prejudice in a sociocultural setting. This would apply to cultures you speak about , as history points out most post-war America and Europe until the defragmentation/ deconstruction theories.
I am reminded of a study which showed that immediately after McCarthyism, Chinese looking for rooms in American hotels were refused in person while accepted when booked over post. These as I see are evolving tangents in an attempt to define and adjust sociocultural roles in the wake of antagonistic challenges. So a Bangalorean pigmy-collecting his detest over a period of time on a North Indian or a Tamilian would be primed to directly react given any available opportunity. The form of the reaction, however is subject to a million personal and communal influences. So a driver may overcharge or a HR may probe further a non-local in an interview or at worst a vehicle with an exotic looking board may be in danger of arson. This would directly lead us to the question of violent expression of prejudice focussing especially on the attack on symbols. In this case that of language. The perception of symbols is one of the great intrigues of human history. I haven’t read or thought as much as I like to have about the topic; I remember Rajesh posting about anatomy of mob violence. A very good authority would be Michel Foucault, and the associated secondary literature he has brought about. The crux is that of process called deindividuation where an individual identity is merged with that of collective action, thus minimising responsibility and hence consequence. E.g. Storming of Bastille, the great Russian revolts from history and any sports violence in recent days.
The other end of spectrum would be that of exercising control and power. Therefore, in cultures where postmodernism and capitalism are central in influencing way of life , language as a means of prejudice is minimal to nil. Prejudice however, being one of the definition of identity from without, would take forms of choice, hence creating an illusion of control. This, means for instance one would hardly see an Italian being discriminated against for his tongue but for his loyalty to a particular football club. In some unfortunate incidents this takes the shape of hostility and violence. Thus , if you pardon a cliché, it comes a full circle.
I remember reading a transcript quite a while back of an interesting talk on sociocultural influences and language between Chomsky and Foucault speaking English and French respectively on Dutch radio! See if you can get hold of it. Quite pertinent.
~ Faces: Hmm, I wonder why people bother so much about reading faces. It is obvious that most face reading is by species instinct and experience, both of which cant be taught. Also, in the eons of hierarchy in civilized populations, most are well adaptable to mask or curtail a real emotion or fake an artificial emotion on the face. So perhaps the whole idea of face reading is bit overrated. I think. So American.
However a few general points we all know would be of symmetry , co-ordination and synchronisation with speech . Of the latter, one mentionable would be the saccades movements of eyeballs. This can be studied scientifically in as a basic Neurolinguistic movements course which would help to gauge the speech and the actual implication in the meaning of a conversation.
I’m sure it could be available somewhere on the net, the basic gist is to watch the face focussing on the eye movements in the context of speech. Outwards and upwards would be visual construction ie fantasy and instantly made up lies. Outwards and upwards to the left would be visual memory. Say recalling a particular space or image relevant to the conversation.
Auditory memory would be left lateral : songs and speech. Internal speech would be left inferior- like conflicts and resolving a dilemma(indecisiveness). This one is particularly useful in negotiations and debates. They also say right inferior is associated with feelings and emotional memory. I have not found this of much use, In fact very few people have this movement in their range. Ill look up the link on these for a detailed explanation. Reckon should be on wiki.
Smile and laughter would be also be a bit useful. But these have strong cultural and class influences hence very little about the individual could be figured from them. Say for instance , Upper class British girl smiling with a brief display of her upper set of teeth can be considered significant while in case of an Iyengar girl in south india it would be the duration of the smile or laughter that would carry any meaning. Again exposure and experience dictates it all. Personally I believe smiles are meant to be enjoyed in an aesthetic sense rather than analytical.
All of these are arbitrary, I’ve known people who being aware of all these practice to remain neutral. Therapists and Police interrogators are trained to remain facially non-judgmental. Its a skill. One other thing to bear in mind would be distance, I reckon a territorial distance of 2m is basic to study faces, to make any reasonable opinion. As I said, the most important would be practice and hence experience; Pecos or Koshys would be a good start, but guess you would be already onto it. Fill up your chicken scrawl notebook that you carry.
One has to always remind oneself that reading faces is an interaction of perceptive values i.e. between two exclusive experiences, so it is absolutely vital in ones own learning interest that he or she has a fairly objective awareness of oneself as well as a good social sense to base the judgement without any figurative bias. So an attractive pair of eyes or a lovely smile would demand a greater effort to eliminate bias. Also, mind you faces mostly reflect emotions, and that too very fleetingly(2-3 seconds); thoughts are usually protected deep down and are always better put into context , body language etc. Even with the emotions , of the 260 odd recognisable human emotions , only six are primary i.e. surprise, anger, disgust, sadness, joy, fear. These are universal, they do not have cultural and language bearings on them. I think this was put forth in a paper in America in the sixties. This remains largely true.
Last but not the least, rule out alcohol, depression and long standing illnesses before bothering about any face . And of course love.
Addenda:
More about eye movements here and there.
On Deindividuation
Kindly eliminate my bias from the above and make your own.