The spelling of the word "vanillon" can be confusing due to its uncommon nature. However, with the help of the International Phonetic Alphabet (IPA), it is easy to understand. The word is pronounced /vænɪljɒn/, which indicates that the "v" sound is followed by the "a" sound, then the "n" sound, and so on. The double "l" represents a lengthened sound, while the final "on" is pronounced with the /ɒn/ sound, similar to the word "gone." Therefore, the correct spelling for this word is "vanillon."