IMO, most foreign languages sound harsh when a man speaks it and sexy when a woman speaks it. Consider Russian, for example. Male speakers don't sound sexy, and most times I've heard a man speaking Russian, it was related to war or politics or something. Female Russians I don't see that way, partially because that's not the role you see them cast in and partially because I had a close (girl) friend in college from Moscow. If you want an even more extreme example, try German. Even French sounds harsh from a man when he's not trying to be romantic, and Frenchmen are often arrogant and condescending, so that's fairly often.
I'm still going to go with Russian for the title question, though.