When it's ano for aņo it's so much fun.

This problem, which arises in written form in Spanish, also exists in spoken form in Italian, with exactly the same words involved. Ano in Italian = ano in Espaņol, anno = aņo - and the difference in pronunciation between one N and two is subtle but noticeable. In my early days of Italian study I would tell people how old I was, without pronouncing both N's in anno, and boy was I the butt of some jokes.