Microsoft was granted a patent for 'Automatic Censorship of Audio Data for Broadcast'. The patent describes a method to censor preselected speech (audio). Our search for the patent reveals the following abstract:
An input audio data stream comprising speech is processed by an automatic censoring filter in either a real-time mode, or a batch mode, producing censored speech that has been altered so that undesired words or phrases are either unintelligible or inaudible. The automatic censoring filter employs a lattice comprising either phonemes and/or words derived from phonemes for comparison against corresponding phonemes or words included in undesired speech data. If the probability that a phoneme or word in the input audio data stream matches a corresponding phoneme or word in the undesired speech data is greater than a probability threshold, the input audio data stream is altered so that the undesired word or a phrase comprising a plurality of such words is unintelligible or inaudible. The censored speech can either be stored or made available to an audience in real-time.