In French, Abby would be spelled "Abby" and pronounced "ah-bee".
However, it's worth noting that Abby is not a very common name in French culture. More common French names with similar sounds include:
* "Abbie" pronounced "ah-bee"
* "Abigaël" pronounced "ah-bee-ga-el"
* "Abigail" pronounced "ah-bee-ga-eel"