1. A system, comprising: a processor; a single microphone configured to both record user speech and to record ambient sounds; and a speech recognition module configured to: identify that the ambient sounds are of a particular type by comparing the ambient sounds to stored waveforms; select a dictionary based on the identified particular type of ambient sounds; identify, as contextual information, terms related to the identified particular type of ambient sounds based on identification of the identified particular type of ambient sounds, the terms being generated as contextual information; alter, in response to identification of the terms related to the identified particular type of ambient sounds, the dictionary such that the dictionary includes the terms related to the identified particular type of ambient sounds; assign, in the dictionary, score values to the terms related to the identified particular type of ambient sounds based on identifying that the terms are related to the identified particular type of ambient sounds; and analyze the user speech by comparing each potential output word or phoneme in the user speech to waveforms stored for the dictionary to attempt to match the potential output word or phoneme to a waveform corresponding to a particular word or phoneme in the dictionary, an analysis varying based on the assigned scores to the terms identified as contextual information.