There may be more language-related research being done in social psychology than you're aware of. Attached is a chapter Jen Pardo and I contributed to a book about connections between social psych and other disciplines.
I was glad to see the chapter, which was published a few years ago as Robert M. Krauss and Jennifer S. Pardo, "Speaker Perception and Social Behavior: Bridging Social Psychology and Speech Science", pp. 273-278 in Paul A.M. Van Lange (Ed.), Bridging Social Psychology: Benefits of Transdisciplinary Approaches, 2006. But reading this chapter, and skimming the rest of the book, confirmed my view that at present, there is remarkably little language-based research in the social sciences.
Their (persuasive) abstract:
Language plays a critical role in social life, and the semantic-pragmatic levels of linguistic analysis has become an important research focus in social psychology. Considerably less attention has been paid to the organized sound system that underlies speech. We distinguish between speech perception, which studies the processes underlying comprehension of the linguistic content of speech, and speaker perception, which examines effects of variability in speech that is not linguistically significant. Much of the latter deals with phenomena that lie at the heart of social psychology. We describe two broad research areas that illustrate the insights consideration of the phonological level of speech can contribute to an understanding of social behavior.
Their (inspiring) conclusion:
In this brief essay, we have argued that the sound structure of speech contains information that can contribute importantly to our understanding of social behavior.
Speaker perception studies the way a particular utterance reflects a speaker's identity and internal state, and his/her definition of the situation. The variability that these factors produce can be studied both as a dependent variable and an independent variable. That is to say, we can examine the effects on voice of inductions involving activated identities, internal state or situational definitions; we also can examine how variability in features of voice (either natural or synthetically created) affect listeners' perceptions of the speaker and the semantic content of the utterance.
I hadn't seen their chapter before, but I know most of the works in their bibliography. And in keeping with the theme of my earlier post, I'll predict that as digital audio archives become more and more available, and computational analysis and synthesis of "voice features" becomes more and more accessible, this kind of work should logically increase in prominence.
After all, when Bob and I overlapped at Bell Labs 30-odd years ago, if you wanted (for example) to compare the "activated identities" of politicians as revealed in their speeches or press conferences, you'd need to buy audio tapes from media companies, have them physically shipped to you, and then digitize and analyze them using million-dollar minicomputers. ("In the snow, uphill, both ways.") Today you can download the audio for free over the internet,do acoustic analysis and synthesis on your laptop, and run perception experiments over the net as well.
But despite Bob's 30-odd years of evangelism from positions of well-deserved authority and respect, and despite the fact that various forms of speech-and-language-based research are becoming easier and easier, it's still not very common for social psychologists to do the sort of research that he persuasively recommends.
The Krauss and Pardo chapter is 5 pages in a 489-page book focusing broadly on interdisciplinary applications of social psychology — and I was unable to find any other discussion in the book of research based on linguistic analysis of any sort. ("Conversation analysis" and "discourse analysis" are mentioned once each, in a parenthetical and essentially contentless sort of way.) This sampled proportion (5/489 = 1%) strikes me as a plausible estimate for the field as a whole.
Again, I predict that this is certain to change, as social-science researchers (and social psychologists in particular) respond to their changing environment. But the cultural conservatism of the academy means that it's going to take a while.