A computing device for performing text-to-speech, "TTS", processing, comprising: at least one processor; a memory device (210, 212) including instructions operable to be executed by the at least one processor to perform a set of actions, configuring the at least one processor: to access a local database of speech units to be used in unit selection speech synthesis, wherein the local database is comprised from a larger database of speech units; to receive text data for TTS processing; to determine desired speech units to synthesize the received text data; to identify first desired speech units in the local database and obtain first audio segments corresponding to the first desired speech units from the local database; to identify second desired speech units in the larger database located at a remote device; to receive second audio segments corresponding to second desired speech units from the remote database; to concatenate the first audio segments corresponding to the first desired speech units from the local database and the second audio segments corresponding to the second desired speech units from the remote database; and to output audio data comprising speech corresponding to the received text data. at least one processor; a memory device (210, 212) including instructions operable to be executed by the at least one processor to perform a set of actions, configuring the at least one processor: to access a local database of speech units to be used in unit selection speech synthesis, wherein the local database is comprised from a larger database of speech units; to receive text data for TTS processing; to determine desired speech units to synthesize the received text data; to identify first desired speech units in the local database and obtain first audio segments corresponding to the first desired speech units from the local database; to identify second desired speech units in the larger database located at a remote device; to receive second audio segments corresponding to second desired speech units from the remote database; to concatenate the first audio segments corresponding to the first desired speech units from the local database and the second audio segments corresponding to the second desired speech units from the remote database; and to output audio data comprising speech corresponding to the received text data. to access a local database of speech units to be used in unit selection speech synthesis, wherein the local database is comprised from a larger database of speech units; to receive text data for TTS processing; to determine desired speech units to synthesize the received text data; to identify first desired speech units in the local database and obtain first audio segments corresponding to the first desired speech units from the local database; to identify second desired speech units in the larger database located at a remote device; to receive second audio segments corresponding to second desired speech units from the remote database; to concatenate the first audio segments corresponding to the first desired speech units from the local database and the second audio segments corresponding to the second desired speech units from the remote database; and to output audio data comprising speech corresponding to the received text data.