After you close your program threads, use the TextToSpeechCloseLang call to close the language. This call accepts the two-character language name of the language to release and then attempts to release the language and its associated files. If other threads are still using the language, the TextToSpeechCloseLang call reduces the instance counter by one for that language. The file is free when all language hooks are freed.
Example:
TextToSpeechCloseLang("uk")