The spelling of the word "one-sidednessed" may seem confusing, but it follows the standard English rules for adding suffixes. The base word "one-sided" is first spelled phonetically as /wʌn-ˈsaɪdəd/. To make it into a past participle form, the suffix "-ed" is added, resulting in /wʌn-ˈsaɪdəd-əd/. Finally, the suffix "-ness" is appended to create the noun "one-sidedness", which is followed by another "-ed" to make "one-sidednessed". Despite its unusual appearance, this word follows the phonetic rules of English spelling.