The spelling of the name "John Mercer" is straightforward: /dʒɒn/ for "John" and /ˈmɜːsər/ for "Mercer". The IPA phonetic transcription breaks down each sound in the word, with "dʒ" representing the "j" sound in "John", and "ɒ" and "ə" representing the vowel sounds in "John" and "Mercer" respectively. The "s" sound in "Mercer" is spelled with an "s" rather than a "c" due to English spelling conventions. Overall, the spelling of "John Mercer" is relatively uncomplicated and follows typical English pronunciation and orthography rules.