The word "haddest title" is spelled with the IPA symbol /ˈhædəst ˈtaɪtəl/. In this case, "haddest" is the archaic second person singular form of the verb "have," meaning "you have." It is spelled with two "d's" to indicate the past tense, as in "had." "Title" is spelled with a single "t" to indicate that it is pronounced with a voiceless sound /t/ rather than the voiced sound /d/ in "had." Together, the correct spelling is "haddest title."