There are two special cases of this equation.
ð ɛ ɹ ɑ ɹ WORD_BOUNDARY t uː WORD_BOUNDARY s p ɛ ʃ ə l WORD_BOUNDARY k eɪ s ɪ z WORD_BOUNDARY ʌ v WORD_BOUNDARY ð ɪ s WORD_BOUNDARY ɪ k w eɪ ʒ ə n WORD_BOUNDARY