16. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: initiating, by a mobile computing device, an audio recording process using a microphone of the mobile computing device; identifying, by the mobile computing device, a first orientation of the mobile computing device at a beginning of the audio recording process; determining, during the audio recording process, that the mobile computing device has transitioned from the first orientation to a second orientation; in response to determining that the mobile computing device has transitioned from the first orientation to a second orientation, determining a speech energy threshold for comparing to speech received during the audio recording process and while the mobile computing device is in the second orientation; comparing an energy of the speech received during the audio recording process and while the mobile computing device is in the second orientation to the speech energy threshold; determining an end of speech condition based on (i) the energy of the speech received during the audio recording process and while the mobile computing device is in the second orientation and (ii) the speech energy threshold; and stopping, based on determining the end of speech condition, the audio recording process.
16. A system comprising: one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising: initiating, by a mobile computing device, an audio recording process using a microphone of the mobile computing device; identifying, by the mobile computing device, a first orientation of the mobile computing device at a beginning of the audio recording process; determining, during the audio recording process, that the mobile computing device has transitioned from the first orientation to a second orientation; in response to determining that the mobile computing device has transitioned from the first orientation to a second orientation, determining a speech energy threshold for comparing to speech received during the audio recording process and while the mobile computing device is in the second orientation; comparing an energy of the speech received during the audio recording process and while the mobile computing device is in the second orientation to the speech energy threshold; determining an end of speech condition based on (i) the energy of the speech received during the audio recording process and while the mobile computing device is in the second orientation and (ii) the speech energy threshold; and stopping, based on determining the end of speech condition, the audio recording process. 20. The system of claim 16 , wherein the operations further comprise: classifying the transition of the mobile computing device from the first orientation to the second orientation as one of a “to mouth” gesture, a “from mouth” gesture, a “to ear” gesture, or a “from ear” gesture, wherein determining the speech energy threshold for comparing to speech received during the audio recording process and while the mobile computing device is in the second orientation is based on classifying the transition of the mobile computing device from the first orientation to the second orientation as one of the “to mouth” gesture, the “from mouth” gesture, the “to ear” gesture, or the “from ear” gesture.