Like Reuters not all words can be dictated to the Nexus One, some are censored. "that's bull #### and you know it." is the result, for example, if you want to use the swear word with the animal excrement. According to Google, this function serves to prevent that "bad" words are accidentally inserted into the text.
Voice input in Android 2.1 is not calculated on the device, but on the Google servers. So if speech recognition is used, data is sent to the Google server and then the translated text is sent back to the device. This makes it possible to update the voice control without the need for phone manufacturers to change anything on their devices - and the performance of the Google servers is many times higher than that of the Nexus One.