13. A system comprising: a data processing apparatus; and a data store storing instructions executable by the data processing apparatus that, upon execution by the data processing apparatus, cause the data processing apparatus to perform operations comprising: receiving, by the data processing apparatus that is operating in a locked mode, audio data that encodes an utterance of a user, wherein the locked mode prevents the data processing apparatus from performing at least one action; providing, while the data processing apparatus is operating in the locked mode, the audio data to a voice biometric engine and a voice action engine; receiving, while the data processing apparatus is operating in the locked mode, data from the voice action engine that identifies a voice action that is associated with the utterance; determining, while the data processing apparatus is operating in the locked mode, that the voice action that is associated with the utterance is classified as a voice action that requires authentication to perform; based on determining that the voice action that is associated with the utterance is classified as a voice action that requires authentication to perform, queuing, while the data processing apparatus is operating in the locked mode, data that identifies the voice action that is associated with the utterance; after queuing the data that identifies the voice action that is associated with the utterance, receiving, while the data processing apparatus is operating in the locked mode, an indication from the voice biometric engine that the user has been biometrically authenticated; and in response to receiving the indication, placing the data processing apparatus in an unlocked mode, and triggering the voice action engine to process a voice the queued action that is associated with the utterance.
15. The system of claim 13 , wherein the voice action is completed by the voice action engine without requiring the user to speak another utterance after the user has been biometrically authenticated.