Jonathan Miller's production of Carmen in English was a huge success at the ENO

The most famous opera works are written in Italian, French or German but some believe that the only way to make opera accessible is to translate them into English.

In America titles and simultaneous translating systems have been praised since their introduction in the 1980s.

But only a very few opera houses in the world retain the practice of singing in English as a policy - among them the English National Opera in London.

Purists maintain that performing opera in translation is artistic sacrilege and singers do find singing in English difficult.

"It is very difficult to sing in English because English is a language that sits very far back in your throat," the celebrated Wagnerian soprano Dame Anne Evans told the BBC.

"Italian, German and French are very forward languages and you have to work particularly hard to sing in our mother tongue."

It does stand to reason that if singing Verdi, Italian vowels sound better than English ones.

What is important is the overall dramatic effect of an opera, an emotional impact, and listeners should not expect to hear every word

Rupert Christiansen

But in fact through most of the 19th century operas were routinely translated into the language of the audience.

Italian Verdi, for example, would have expected his Il Trovatore to be sung in French for a French audience.

But opera-goers - like the one who wrote to the newspaper this week - do complain that it is difficult to understand the English of opera singers.

Some, like Dame Anne, blame the singers involved.

"I think its our job to make the text clear," she said.

"When I was a young singer they always had somebody sitting out front with a paper and pencil, taking notes if they couldn't understand the text and if we don't make the text clear we've failed in our job."

But others are kinder to singers, like the Telegraph's Rupert Christiansen.

"I think the real problem is the audiences," he said, adding that in his opinion we are spoilt by CD clarity sound and electronically-controlled volume.

The ENO's Barber of Seville in English was a big hit with our celebrity reviewer

"When we go into a natural acoustic environment we can't really be bothered to listen properly," he said.

Dame Anne, too, bemoans technological innovations, but she feels the effect is on performers rather than the audience.

She points to similar problems for theatre-goers, who complain they often cannot hear the words of a play.

"I think in the theatre, people are so used to working on television with microphones and end up mumbling," she said.

Ultimately, she said, perhaps people should be bothered less about the word for word meaning of a play or opera, and focus instead on the overall impact.

"What is important is the overall dramatic effect of an opera," said Christiansen.

"Its an emotional impact, and listeners should not expect to hear every word."