For example, the Italian and French words for various foods, some family relationships, and body parts are very similar to each other, yet most of those words are completely different in Spanish. Italian "avere" and "essere" as auxiliaries for forming compound tenses are used similarly to French "avoir" and "être". Spanish only retains "haber" and has done away with "ser" in forming compound tenses. However, when it comes to phonological structures, Italian and Spanish have undergone less change than French, with the result that some native speakers of Italian and Spanish may attain a degree of mutual comprehension that permits extensive communication.[citation needed]
Which two languages have undergone more change than French regarding phonological structures?