1. A computer-implemented method for text-to-speech (TTS) synthesis, the method comprising: in response to a word of a text sequence, generating a first part-of-speech (POS) tag using a statistical POS tagger based on a corpus of trained text sequences, each representing a likely POS of a word for a given text sequence; generating a second POS tag using a rule-based POS tagger based on a set of one or more rules associated with a type of an application associated with the text sequence; and assigning a final POS tag to the word of the text sequence for TTS synthesis based on the first POS tag and the second POS tag.