Can cats understand English?

You would think that cats could understand English but I'm not so sure they do. When you shout their name you think they understand you but they could just be replying to your tone of voice. My auntie had a cat that always tried to drink her tea and she always understood the word NO! But yet again it could just be the tone of voice as when my auntie said NO she said it in a very sinister way! What doyou think, can cars understand English?!?