1. A method for providing text-to-speech (TTS) functionality to a telematics unit of a telematics-equipped vehicle in a networked system, the method comprising: receiving, by a processor of the telematics unit or a remote TTS engine on a remote server, text content to be played back by an audio system of the telematics-equipped vehicle; determining, by the processor of the telematics unit or the remote TTS engine on the remote server, a TTS rendering process type to be used for the text content from a plurality of TTS rendering process types supported by the networked system, wherein the plurality of TTS rendering process types include: a local TTS rendering process using a local TTS engine at the telematics-equipped vehicle, a remote TTS rendering process with delayed playback using the remote TTS engine, and a remote TTS rendering process with streaming playback using the remote TTS engine; and causing, by the processor of the telematics unit or the remote TTS engine on the remote server, the text content to be rendered as an audio signal for playback by the telematics-equipped vehicle using the determined TTS rendering process type; wherein the determining is based on a quality of service (QoS) level corresponding to a location of the vehicle and a future expected location of the vehicle, and wherein during the determining, the TTS rendering process type is specified as: the local TTS rendering process for a current location corresponding to a first range of QoS levels, the remote TTS rendering process with delayed playback for a current location corresponding to a second range of QoS levels and for an expected transition from a current location corresponding to a third range of QoS levels to a future expected location corresponding to the first or second range of QoS levels; the remote TTS rendering process with streaming playback for a current location corresponding to the third range of QoS levels when there is not an to an expected transition to a future expected location corresponding to the first or second range of QoS levels.
5. The method according to claim 1 , wherein the remote TTS rendering process with delayed playback comprises determining an amount of content to buffer prior to playback.