There are three main systems related to the verb: tense, aspect, and mood.
ð ɛ ɹ ɑ ɹ WORD_BOUNDARY θ ɹ iː WORD_BOUNDARY m eɪ n WORD_BOUNDARY s ɪ s t ə m z WORD_BOUNDARY ɹ ɪ l eɪ t ɪ d WORD_BOUNDARY t ə WORD_BOUNDARY ð ə WORD_BOUNDARY v ɜː b WORD_BOUNDARY t ɛ n s WORD_BOUNDARY æ s p ɛ k t WORD_BOUNDARY æ n d WORD_BOUNDARY m uː d WORD_BOUNDARY