Why does the French language sound so different from the other Romance or Latin languages?

These answers are kinda converging. My answer is:

• What Brian Collins said—the vowel repertoire, plus the final consonants,
• and the nasals. There are nasals elsewhere, including Vulgar Latin; but the nasals are a huge part of the French stereotype. [hɔ̃.hɔ̃.hɔ̃]
• Grudgingly, I admit that the nasals are less critical than the other two. I hate both Portuguese and French because of the nasals; but noone confuses Portuguese and French.

I was reading some Old French out loud one day two decades ago, while doing my PhD. And I turned to my bolshie (literally) fellow PhD student, and commented “hey, Old French actually sounded quite nice”.

“Yeah,” he snarled. “Before it picked up all that froggie shit.”

aka: How French got all its Froggie Shit.