The spelling of the word "haddest tree" may seem unusual, but it is actually a correct spelling in the English language. The word "haddest" is the second-person singular past tense of the verb "have" and is pronounced as /ˈhæd.əst/ in IPA phonetic transcription. Meanwhile, "tree" is simply pronounced as /triː/. It is important to note that this spelling may be less common in modern English, but it was commonly used in Early Modern English and is still occasionally seen in poetry or in other literary works.