1. A method of adjusting a speech engine for a mobile computing device based on background noise, the mobile computing device operatively coupled to a microphone, the method comprising: determining whether a previously-generated background noise model exists for a current operating environment of the mobile computing device; and if it is determined that no previously-generated background noise model exists for the current operating environment: sampling, through the microphone, background noise for the current operating environment, generating a background noise model based at least in part on the sampled background noise, and configuring the speech engine for the mobile computing device with the background noise model.