The spelling of the word "Humbertson" may seem a bit unusual, but it can be easily explained using IPA (International Phonetic Alphabet) transcription. The first syllable is pronounced as "hʌm," which sounds like "hum" but with a shorter vowel sound. The second syllable is pronounced as "bɜːrt," with the "er" sound being emphasized. Lastly, the final syllable is pronounced as "sən," which sounds like "sun" but with a shorter vowel sound. Therefore, the correct spelling of "Humbertson" can be remembered by breaking it down phonetically: "hʌm-bɜːrt-sən."