The spelling of the word "in expertnesses" is quite complex. Firstly, the prefix "in" is pronounced with an "ɪn" sound. The following word "expertnesses" is made up of three syllables: "ex-pert-nesses". The "ex" is pronounced with an "ɛks" sound, the "pert" with a "pɜrt" sound, and the final syllable "nesses" with a "nɛsɪz" sound. All of these sounds come together to create the unique spelling of "in expertnesses". However, this word is not commonly used in everyday language.