Victor and Sibyl both use nicknames for Amanda and Elyot (Mandy and Elli), though Amanda and Elyot always refer to each other by their full names. What is the significance of the use of nicknames in regards to these four characters?

Victor and Sibyl use the shortened versions of their spouses' names as a term of endearment and affection. However, it can also be seen as a way to make Amanda and Elyot more approachable to Victor and Sibyl. Amanda and Elyot are very worldly, sophisticated people and their new spouses appear to be somewhat intimidated by their experiences. Using shortened, almost childish versions of their names make Amanda and Elyot seem more like their spouses. It is also worth noting that Amanda and Elyot do not use nicknames for anyone and it is not mentioned in this act whether they like their nicknames. If it is assumed that they do not care being called "Mandy" or "Elli," then it is also an indication of how very little Victor and Sibyl know their spouses.