To determine whether women and men talk differently there are three main aspects to be considered; firstly does the language actually differ? How does it differ? and why do women and men talk differently. Evidence for this has stemmed from anthropology, dialectology, sociolinguists and social psychology. There is certainly plenty of evidence of differences between women and men in the area of language. For instance, girls are seen as verbally more precocious than boys (Maccoby and Jacklin 1974; Chambers 1992). "Over many years, women have demonstrated an advantage over men in tests of fluency, speaking, sentence complexity, analogy, listening, comprehension of both written and spoken material, vocabulary, and spelling" (Chambers, 1992). By contrast "men are more likely to stutter and too have reading disabilities. They are also much more likely to suffer aphasic speech disorders after brain damage...males are also four times more likely to suffer infantile autism and dyslexia than are females" (Chambers, 1992). It therefore appears that females are initially at an advantage in terms of such verbal skills, and this may be a starting point to why women and men use language differently.
The aspect of gender differences in language can be described by two different categories. One of these being Sex-based differences that is inherent to the language system. Every language has a set of basic elements such as phonemes and morphemes; and a general set of rules that all native speakers have the same knowledge of. However, in some languages some of these rules are dependent on the gender of the language user (Brouwer, Gerritsen & Haan, 1979) in some languages there is one guideline for males and another for women. More interestingly however is the degree to which there are gender-based differences in this language use, specifically concentrating on the extent of how the basic rules of language are used and in what combination or preference. One very general belief of why there is a gendered difference between men and women's language use is based on the social dominance of men over women. The idea of women's insecure social position seems to give rise to the way a woman talks and uses the language rules set within her society.
In terms of conversational patterns, it has been observed or claimed that women use more verbal "support indicators" like "mm-hmm" than men do: that men interrupt women more than they interrupt other men, and more than women interrupt either men or other women; that women express uncertainty and hesitancy more than men; and that males are more likely to give direct orders than females are. However, for nearly all these claimed differences there are of course some contradictory findings. Yet because of the enormous effects on social and interpersonal context on all the variables involved, and the enormous range of individual differences among people of all sexes, both in general and in their responses to differing circumstances, and the strong effect of social stereotypes on experimenter's interpretations as well as on their subjects behavior, this is an especially difficult kind of topic to study. People and social circumstances are variable and complicated, and its clear that you need to look at the details in order to predict behavioral tendencies, much less individual behavior.
As for the explanation of the gendered speech differences, there are biological "evolutionary psychology" theories, and two classes of culture-based theories, generally known as difference theories and dominance theories. According to difference theories, men and women inhabit different cultural worlds. To quote Deborah Tannen's 1990 popularization "you just don't understand", "boys and girls grow up in what are essentially different cultures, and so talk between women and men is cross-cultural...