Assumpta gave me a crash course in cat language. You can mimic meows all day long, but it won't mean much to the cat, as it's mainly a one-way communication method they use to communicate with humans (adult cats don't meow at each other; they have better ways of communicating).
Blinking, yawning, and washing are all nice, non-threatening ways to communicate with your cat. And I will second what Tim said about hissing and growling and other communications of territoriality and aggression: You had BETTER know what you're saying and when to say it, or you chance escalating an aggressive episode and either being injured or damaging your relationship with your cat. I'll go face-to-face with Assumpta when she's acting up, but only because I know how she reacts and what she'll do...to date, I'm the only person she'll back down from; I've never hit, yelled at, or scared her, but I've tried to make myself look like the bigger, more powerful cat using body language and occasional vocalizations. She's either bought it or she thinks it's funny and forgets whet she was mad about.
She'll start getting pushy with me, I'll challenge her in body language, and she'll consider it for a minute and then start washing or yawn...that's my cue to join her in non-threatening gestures, ending in patting and cuddles. I don't use body language methods with shelter cats, because they will certainly go to homes where they'll need to understand human language, so I use only people-talk and human postures...a shame, because there are a few that I think I could work with using a more cat-centered approach, but I have my orders.
I love slow-blinking. Assumpta will lie on my chest with her face in mine, nose-to-nose, and we'll swap slow blinks until one of us falls asleep. Makes me all sappy and sentimental.