The spelling of the word "Assa doux" is influenced by the French language, which is known for its varied pronunciation rules. The word is pronounced /asa du/, with the "s" in "asa" being pronounced as "z" due to the following vowel. The "doux" part is pronounced as /du/, with the "x" being silent. The spelling of the word stays true to French language rules, where consonants often have different sounds when paired with certain vowels.