[Mithalwen]

Although I think the letter to Rayner Unwin has been mentioned, "The Lord of the Rings - A reader's companion" (Hammond &Scull - Calcifer!!) has the full list of names Tolkien felt should be translated with notes- it runs to some thirty printed pages so it is clearly something he cared about very much - as is to be expected for someone who felt the way he did about language. Also many of the hints and references are not obvious even to a native speaker such as myself who has studied linguistics, languages and literature to degree level. It is usual to translate into the mother tongue so I imagine that non native speakers might benefit from this insight - even though their studies and intelligence be no doubt superior to mine.

But it is hard for me to say because I haven't read Tolkien in any other language - and having loathed some of the name translations in the French Harry Potter I don't know whether it would be a good idea.

Anyway if you have access to the reader's companion it is a fascinating read.