Here's an interesting little article about "the Cheerios effect" (I kid you not), in which Cheerios in a bowl of milk will clump together and aggregate at the sides of the bowl - and how this relates to space!
I think this article is particularly interesting because of the way it shows that simple everyday effects can be observed on vastly larger scales. The underlying truths of a world (physical laws in this case) are observable on multiple different levels.
This is also true of language. The most fundamental principles of a language, whether strictly grammatical or pragmatics-related, can generally be observed even in very small recorded samples of speech in that language. As examples I'd give grammatical gender in French and Spanish, and casual versus formal speech style in Japanese (though there are many more). I find the speech style example particularly interesting because it has social consequences, not just grammatical ones. This is where you start seeing that this phenomenon also reaches into the area of culture.
I've been writing this week in my Varin world, and rejoicing at the fact that I'm so much a better writer now than when I first designed it. The reason why? Well, because when you first design a world it's really easy to lay out a lot of general principles about how the society works. It's much harder to explore how those general principles play out on the smaller scale of individual interactions.
If you say, "The nobility are isolated and think they're better than anybody else," it's easy to have them go around acting too broadly. They dress and speak loudly, they insult others, they just basically act like arrogant snobs in a really really obvious way. I am embarrassed to say that this is what they were like when I first wrote them. However, this isn't really how things work. These are people like everyone else, and they should have just as many arrogant snobs among them as other social groups do - which is to say, not everyone. A single individual's main personality traits should be at the fore (as for example, my relatively modest and kind protagonist, Tagret); their cultural bias should be reflected on the small scale in their unconscious reactions.
To explore a bit further into the Varin example, the nobility of Varin typically don't mix with any caste but the servant caste, who are an integral part of their everyday life. They can be either polite or impolite to their servants depending on the person. They have dealings with the officer caste (police, army, fire brigade etc.) in certain fixed contexts. However, they almost never see anyone of lower caste than that. An insensitive nobleman or noble lady, having to deal with merchants or artisans, might express distaste, but someone like Tagret feels mostly out of his depth, like he doesn't know what to do with them. He tries to be polite but at the same time will try to distance himself from them, unconsciously, to remove himself from the discomfort of not knowing the appropriate way to treat these people socially.
If your world has social principles, treat them as respectfully as you would the laws of physics. Don't just slap them on over the top. Realize that just like the Cheerios effect, they will have repercussions that go all the way down to the smallest interactions, including the subtleties of the ways people talk to each other.