It is always fun to see how translation tools seem to change the message when you translate from one language to another, then back again. Say, for example, you want to say "Katja's mom is very nice" from English to Spanish. So you go to http://www.google.com and select the "language tools" to start translating. And then you know what to say in Spanish.
However, will they understand what you are saying? Copy&Paste the translated text and translate it back from Spanish to English and you will realise that you might have said something very different instead.