The spelling of the word "thed" may seem confusing at first glance, but it actually follows the pattern of regular past tense verbs. The "th" sound is represented by the IPA symbol /ð/, while the "-ed" ending is pronounced as /d/ or /t/ depending on the final consonant sound of the base verb. In this case, the base verb is "the," which ends with a voiced /ð/ sound, so the past tense ending "-ed" is pronounced as /d/. Therefore, "thed" sounds like /ðɛd/.