7. A system, comprising: a communication device; and a processor programmed to: create, responsive to determining to transition a voice call from voice communications over a voice network to streamed text over a packetized data network, a voice conversation correlation identifier that identifies the voice call and specifies incoming and outgoing streamed text data as part of the voice call; convert additional outgoing speech spoken by a user associated with the voice call to streamed text data; send, via the communication device, the streamed text data identified by the voice conversation correlation identifier within an outgoing text stream over the packetized data network; receive, via the communication device, streamed response text data identified by the voice conversation correlation identifier within an incoming text stream over the packetized data network; and convert the received streamed response text data within the incoming text stream to speech output as part of the voice call; where, in being programmed to receive, via the communication device, the streamed response text data identified by the voice conversation correlation identifier within the incoming text stream over the packetized data network the processor is programmed to one of: receive text advertisement content within the received streamed response text data within the incoming text stream associated with a subject matter of the voice call and rendering the text advertisement content during the voice call; or receive text represented in a different language from a language spoken by the user and performing a language conversion of the text represented in the different language to the language spoken by the user, where the received streamed response text data converted to the speech output comprises the language-converted text.
7. A system, comprising: a communication device; and a processor programmed to: create, responsive to determining to transition a voice call from voice communications over a voice network to streamed text over a packetized data network, a voice conversation correlation identifier that identifies the voice call and specifies incoming and outgoing streamed text data as part of the voice call; convert additional outgoing speech spoken by a user associated with the voice call to streamed text data; send, via the communication device, the streamed text data identified by the voice conversation correlation identifier within an outgoing text stream over the packetized data network; receive, via the communication device, streamed response text data identified by the voice conversation correlation identifier within an incoming text stream over the packetized data network; and convert the received streamed response text data within the incoming text stream to speech output as part of the voice call; where, in being programmed to receive, via the communication device, the streamed response text data identified by the voice conversation correlation identifier within the incoming text stream over the packetized data network the processor is programmed to one of: receive text advertisement content within the received streamed response text data within the incoming text stream associated with a subject matter of the voice call and rendering the text advertisement content during the voice call; or receive text represented in a different language from a language spoken by the user and performing a language conversion of the text represented in the different language to the language spoken by the user, where the received streamed response text data converted to the speech output comprises the language-converted text. 9. The system of claim 7 , where, in being programmed to determine to transition the voice call from the voice network to the streamed text over the data network, the processor is programmed to one of: detect signal degradation of the voice network; or determine to insert an outgoing advertisement into the voice call and insert outgoing text advertisement content of the outgoing advertisement into the outgoing streamed text data.