A computer-implemented method, comprising: obtaining, by one or more processors of a communications device (110, 650), a library of components for a voice-user interface, the communications device storing a plurality of client application programs for execution; executing a particular client application program of the plurality of client application programs using the one or more processors, each client application program being linked to a corresponding one of the components from the library of components for the voice-user interface, the components being linked to a voice-service provider application executed by the communications device; generating, by the one or more processors, a native graphical user interface for the executed client application program, the native graphical user interface comprising first interface elements, the first interface elements comprising content associated with the executed client application program; generating, by the one or more processors, a second interface element representative of the corresponding one of the components; embedding, by the one or more processors, the second interface element into the native graphical user interface for the executed client application program; presenting, by the one or more processors, the native graphical user interface comprising the first interface elements and the embedded second interface element through a display unit of the communications device, wherein selection of the embedded second interface element initiates voice-based interaction and control of the executed client application program through the voice-service provider application; providing, by a client application module of the communications device and to the voice-service provider application, contextual data that characterizes content currently being presented within the native graphical user interface; receiving user input indicative of a selection of the embedded second interface element and performing, in response to the received user input, operations that activate a microphone of the communications device; capturing, by the microphone, audio data indicative of an utterance spoken by a user and providing the audio data to the voice-service provider application; packaging, by a query module of the voice-service provider application, portions of the audio data and contextual data into query data; transmitting the query data to a remote computing system associated with the voice service provider; receiving a structured response bundle from the remote computing system, the structured response bundle including data instructing the executed client application program to perform one or more actions consistent with the determined meaning of the spoken utterance; and performing, by the communication device, the one or more actions. obtaining, by one or more processors of a communications device (110, 650), a library of components for a voice-user interface, the communications device storing a plurality of client application programs for execution; executing a particular client application program of the plurality of client application programs using the one or more processors, each client application program being linked to a corresponding one of the components from the library of components for the voice-user interface, the components being linked to a voice-service provider application executed by the communications device; generating, by the one or more processors, a native graphical user interface for the executed client application program, the native graphical user interface comprising first interface elements, the first interface elements comprising content associated with the executed client application program; generating, by the one or more processors, a second interface element representative of the corresponding one of the components; embedding, by the one or more processors, the second interface element into the native graphical user interface for the executed client application program; presenting, by the one or more processors, the native graphical user interface comprising the first interface elements and the embedded second interface element through a display unit of the communications device, wherein selection of the embedded second interface element initiates voice-based interaction and control of the executed client application program through the voice-service provider application; providing, by a client application module of the communications device and to the voice-service provider application, contextual data that characterizes content currently being presented within the native graphical user interface; receiving user input indicative of a selection of the embedded second interface element and performing, in response to the received user input, operations that activate a microphone of the communications device; capturing, by the microphone, audio data indicative of an utterance spoken by a user and providing the audio data to the voice-service provider application; packaging, by a query module of the voice-service provider application, portions of the audio data and contextual data into query data; transmitting the query data to a remote computing system associated with the voice service provider; receiving a structured response bundle from the remote computing system, the structured response bundle including data instructing the executed client application program to perform one or more actions consistent with the determined meaning of the spoken utterance; and performing, by the communication device, the one or more actions.