The two sexes are involved in a perennial effort to impress one another in the mating arena. One of the most common sex-specific ways of sexual signaling is for men to use cues of high social status (see my earlier post here on the links between men's testosterone levels and their driving a Porsche) whereas women utilize beautification (see my earlier post here on the effects of cosmetics at a bar). 
In surveys on mating preferences administered around the world, both men and women proclaim that intelligence is an essential trait for prospective mates to possess. One of the means by which intelligence can be gauged is via one's vocabulary. Accordingly, it might be expected that one's lexicon must serve as a sexual signal.

In 2008, Jeremy Rosenberg and Richard J. Tunney published a paper in Evolutionary Psychology wherein they verified the use of vocabulary by both men and women subsequent to having been primed about having a romantic date with young partners versus interactions with opposite-sex older individuals. In other words, subsequent to the prime, they were asked to respond to a question that sought to gauge their student life experiences, future aspirations, etc. The dependent measure was the rarity of words that they used in their responses (as gauged via the British National Corpus). Obviously, words that occur less frequently (i.e., are more rare) are indicative of a more sophisticated vocabulary.

Here are the key results: Men used less frequent words subsequent to the romantic prime. On the other hand, women used words of higher frequency (the effect only reached marginal statistical significance) following the romantic prime. The authors suggest that this might be an attempt by women to play the "dumb" card, as a means of catering to men's preference to date women who are less intelligent than them.

Bottom line: It would appear that men are more likely to utilize their lexical abilities in seeking to impress women.