I feel inclined to explain the Words and Music chapter from Divas and Scholars, assuming I understand it myself.
Opera has two great traditions: the Italian and the French. The first French Opera was six decades behind the first Italian Opera, but unlike operas in other countries, such as Germany and England, Pomone by Robert Cambert in 1671 firmly established a vogue for opera in French, a vogue that was quickly exploited by Lully. He was followed by Rameau, Gluck (his biggest success and most important influence was in France), Cherubini, Salieri (a lot of Italians wrote operas in the French style), etc. In Rossini’s time Spontini and Mehul were the main French opera composers. The French developed their own comic opera tradition, too, starting in the late Baroque/early Rococo and continuing through Carmen and so on.
Each country established its own independent tradition. By the time of Rossini the Italian tradition was over 200 years old and the French tradition a more youthful 140 years. I don’t recall any French composers who moved to Italy, but the list of names above gives a clear indication that a lot of Italian composers, including all of Gossett’s quadrumvirate: Rossini, Bellini, Donizetti and Verdi, wrote French operas for Paris. Paris was simply too lucrative a market to ignore. No one but the Germans Handel and Johann Christian Bach seem to have regarded London as a place to move to.
When the Italians wrote for the French market, it might be an Italian opera they were writing, such as Il Viaggio a Reims by Rossini, but more likely, they composed French operas for the French, using their style and their librettos. An opera generally starts with a libretto. Both countries developed a style of poetry that they deemed suitable for an opera libretto and composed music in their own style. In the case of the French this generally included ballet. Louis XIV was a ballet enthusiast--in his youth he was a ballet dancer as well--and the tradition stuck. Sticking in ballets and taking them back out again is not really a problem.
None of this would have been a problem had it been considered suitable to simply translate an opera from French to Italian or from Italian to French. If the composer was Italian, the only side of the equation Gossett is concerned with, the Italians wanted the result to be an Italian opera and not merely a translated French one. So the Italians rewrote the French operas to be Italian operas with more or less the same music but completely different poetic forms, with the result that the Italian versions are not really what you would call versions. They’re different operas.
This seems a problem with a simple solution: write new translations. We in the English speaking countries do it all the time and don’t really understand why this is a problem. Every 25 years or so we tire of old translations and want new ones. Germans are excellent translators and are adept at finding exactly the right German words to capture the original. The German translation of My Fair Lady is awesome.
This appears not to work for the Italians. Sensitivities are upset. Toes are stepped on. Traditions are violated. Perhaps they have learned to love their version and don’t want to give it up. What is one to do?
I have oversimplified, as usual. The biggest problem, it seems to me, is that in countries not either Italy or France it is the Italian version that is performed. We should not presume to speak for the Italians, but we can certainly speak for ourselves. When the San Francisco Opera presented Donizetti's La Favorite in 1973, it was in the Italian version. In the 1999-2000 season SF presented the French version. We shall regard this as progress. At the Met this opera has not been presented since 1978, but all the performances have been in Italian. I know that when I learned the aria, it was called in Italian "O mio Fernando."
Verdi's Sicilian Vespers was sung in Italian at the Met as recently as 2004. Donizetti's Daughter of the Regiment seems always to have been sung in French.
Frankly, there is a prejudice against French caused by the ghastly manner in which it is often sung. I am pleased to say that I did not experience any of my usual nausea about the pronunciation of French in Los Angeles Opera's Manon. Anna continued to sound like herself. Her voice didn't disappear into her head when she tried to do nasals, as is so often the case.
I feel inclined to promote the fortunes of La Favorite because it is one of those rare operas with a mezzo heroine, and Professor Gossett makes his best arguements relative to this opera. A dramatic mezzo should champion it. In French.