I'm Italian, but this is a question of style. AP style may explain why a few titles weren't translated


Translate Foreign Works and Titles Into English
Unless the title of a work is well-known in its foreign language, always translate the title or work into English, remembering that the goal of AP style is to simplify the reader's job, not complicate it.

Examples include:

•Kafka's "The Metamorphosis" not "Die Verwandlung"
•Maupassant's "The Necklace" not "La Parure
•But "Die Walkuere" and "Gotterdammerung" from Wagner's "The Ring of the Nibelungen"




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Note added at 30 mins (2012-04-18 16:20:43 GMT)
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This means you would probably have to translate them all

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Note added at 39 mins (2012-04-18 16:29:38 GMT)
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see also under Naming articles:

Books, movies and other media that were translated or renamed for their English publication or distribution should be created using the name they are best known by English speakers. Camus' novel would be found at The Stranger and not by its orignal title L'Étranger.
Books, movies and other media that were translated or renamed for their English publication or distribution should be created using the name they are best known by English speakers. Camus' novel would be found at The Stranger and not by its orignal title L'Étranger.
http://en.wikipedia.org/wiki/Wikipedia_talk:Manual_of_Style/...