I am interested in historical phonetic development process which resulted in French having so many vowels in comparison to other Romance languages, and even more than Latin, which I believe had only 6 vowels not counting long-short differences.
All Romance languages descend from Latin, right? And yet Spanish, Italian have only a few vowels, while French has many more. Why the difference? Was French influenced by different languages than the others? Was there a difference in the time period where French phonology developed? Different response to Latin long and short vowels?