The spelling of the word "TOTALN" can be explained through its International Phonetic Alphabet (IPA) transcription: /toʊtəln/. The first syllable "TO" is pronounced as "toʊ" with a long "o" sound, followed by the "TAL" which is pronounced as "təl" with a schwa sound. Finally, the last syllable "N" is pronounced as "n" itself. Therefore, "TOTALN" is spelled with an "O" instead of the traditional "U" to indicate the long "o" sound in the first syllable.