The spelling of the word "nusser" can be explained using the International Phonetic Alphabet (IPA). The first syllable is pronounced as "nʌs", with the "u" sounding like the "u" in "up". The second syllable is pronounced as "ər", with the "ə" sounding like the "u" in "about" and the "r" being a very soft and subtle sound. Therefore, "nusser" is spelled phonetically as "nʌs-ər". It is important to use accurate IPA transcriptions when studying and learning pronunciation in different languages.