1. A method for a computing device, the method comprising: during a first speech detection mode, the computing device: capturing first audio, detecting first speech in the captured first audio, comparing the detected first speech to a plurality of activation phrases to identify any potential matches based on a first language model, wherein the plurality of activation phrases is associated with a plurality of applications on the computing device such that each application in the plurality of applications is associated with a respective activation phrase in the plurality of activation phrases, and wherein the first language model covers the plurality of activation phrases, and in response to identifying a matching activation phrase within a confidence threshold, invoking the application in the plurality of applications associated with the matching activation phrase and entering a second speech detection mode; and during the second speech detection mode, the computing device: in response to entering the second speech detection mode, reducing the confidence threshold, capturing second audio, detecting second speech in the captured second audio, obtaining a recognition result of the detected second speech based on a second language model, wherein the second language model has a wider coverage than the first language model, determining whether the recognition result is identified within the confidence threshold, and after determining that the recognition result is identified within the confidence threshold, providing the recognition result to the invoked application.