Automatic conversion between pronunciations of different English accents

We describe the application of decision trees to the automatic conversion of pronunciations between American, British and South African English accents. The resulting phoneme-to-phoneme (P2P) conversion technique derives the pronunciation of a word in a new target accent by taking advantage of its existing available pronunciation in a different source accent. We find that it is substantially more accurate to derive pronunciations in this way than directly from the orthography and available target accent pronunciations using more conventional grapheme-to-phoneme (G2P) conversion. Furthermore, by including both the graphemes and the phonemes of the source accent, grapheme-and-phoneme-to-phoneme (GP2P) conversion delivers additional increases in accuracy in relation to P2P. These findings are particularly important for less-resourced varieties of English, for which extensive manually-prepared pronunciation dictionaries are not available. By means of the P2P and GP2P approaches, the pronunciations of new words can be obtained with better accuracy than is possible using G2P methods.