The spelling of the surname "Brummitt" is derived from its pronunciation. It is phonetically spelled as /brʌmɪt/ in the International Phonetic Alphabet (IPA). The first syllable is pronounced with a short vowel sound /ʌ/, followed by a consonant cluster /m/ and /ɪt/. The spelling of this surname can also be influenced by regional accents, leading to variations in spelling. Overall, the phonetic spelling serves as a precise method to understand the correct pronunciation of the name Brummitt.