The current standard obsoletes these former versions:
ð ə WORD_BOUNDARY k ɜː ɹ ə n t WORD_BOUNDARY s t æ n d ə ɹ d WORD_BOUNDARY ɑ b s ə l iː t s WORD_BOUNDARY ð iː z WORD_BOUNDARY f ɔ ɹ m ə ɹ WORD_BOUNDARY v ɜː ʒ ə n z WORD_BOUNDARY