Semantically conditioned voice activity detection

A method comprising:

• recognizing words within an utterance of a user by a speech recognition engine to generate one or more transcription hypotheses;
• interpreting, by a natural language understanding processor, the recognized words by comparing the transcription hypotheses to a plurality of semantic grammars respectively associated with a plurality of domains, each semantic grammar producing a probability score representing a likelihood that the utterance corresponds to the respective domain;
• from the interpreting of the recognized words, determining by the processor, a weighted-average timeout period for the utterance as a weighted average of domain-specific timeout values, each domain-specific timeout value being multiplied by its corresponding probability score and divided by a sum of the probability scores;
• detecting an end of voice activity in the first utterance using a voice activity detector coupled to a microphone sensor;
• and
• executing, by the processor, an instruction following an amount of time after detecting the end of voice activity, the instruction being executed in response to the amount of time exceeding the determined weighted-average timeout period, and being based at least in part on the interpreted words.