Narnian philological problems:
Do Narnians speak English, Telmarines too?
Where do Narnian names come from?
Do Narnians speak English, Telmarines too?
Actually, it would seem so. Narnia's Archenland's and even Calormen's original Kings and the ancestors of their first human populations all come from King Frank and Queen Helen who were fetched by Aslan from London. Telmarines seem to have been originally pirates who, despite a Spanish twinge to their names - or pseudospanish - may well be anglophones.
So, how English children communicate in Narnia is not a problem. However, between King Frank and the arrival of the Pevensies, it seems the Narnian English grew more Shakespearean. A development which C. S. L. may well have thought humanly possible and achievable by stylistic and artistic will. Cf. his essay "What Chaucer really did to Il Filostrato" (Selected Literary Essays ). The only communication that would seem to involve magic is when two children from London visit Charn. An older and more fallen world than Atlantis.
Remaining mystery: if everyone speaks English, why do some have so very exotic and yet national, and nearly none (except arrivals from England) English names? Might be because a) English take exotic names anyway and b) because people who started taking similar names also continued to live together c) English sounding names were the kind of nicknames given to dwarfs (Trumpkin), giants (Rumblebuffin) and centaurs (Roonwit). They are so dialectal, I strictly leave them to English specialists. At least for now.
Where do Narnian names come from?
Narnia - as already noted by C. S. L. and known by everyone, is the Latin name of present day Narni, in Italy. Aslan is Turkish for "lion". Jadis is French for "formerly". Those too were answered by C. S. L. As well as Caspian, a reference to Armenian surnames and the fact that there is a sea called the Caspian sea.
Let us stay in France for a while. Aravis is a mountain range in Haute-Savoie, as I found out yesterday. Shasta is an Amerindian ethnicity and a mountain in CA: Mount Shasta. Looking at the map is always a good way to find odd sounding and yet familiar names/words. C. S. L. recommended it in his letters to the god daughter who went on to write fantasy herself, see Letters to children. Mavramorn - well morne is French for "sullen" (or something like it) and mavros is Greek for "black". From which name I think Avra and Doorn also come: Mavramorn - letter M = .avra.orn and the latter rhymes with German Dorn (=thorn), add an o to change pronunciation, so as to avoid a direct rhyme with Mavramorn. Now for Felimath - well Latin felix (=happy) would be by the French pronounced feli, add Irish math (=good).
And Coriakin: take French coriace (=tough) latinize it to coriacem, classic pron. coriakem, then off the acc. ending, then on an Irish diminutive ending -ín (-een). Which diminutive ending is also behind the names of younger brothers in Archenland: Cor and Corin, Dar and Darin, et c.
Dr. Cornelius - tells Caspian a tragedy leading to his exile from court and knows several lives - reminding of Corneille, author of exile tragedy Le Cid and of Cornelius Nepos, Latin author of biographies of "Famous men".
De même, le premier voyage de Lancelot en Sorlois, son premier passage sur l'un des deux ponts, espèces de forteresses, constitue le point de départ d'une ...
as well as a possible adjective for the placename Saint-Sorelin-de-Vienne (scroll down until yellow mark shows research).
And so on, and so on ... (updates may show up)
There is about one source C. S. L. did not use: he did not invent languages like Tolkien (see Ardalambion) in order for names to have a linguistic character of those languages by derivasion from them.
Probably the indications about King Frank and Queen Helen, as well as the origin of the Telmarines, were added on account of a philologer like abovementioned criticizing the scenario from that point of view.
Aix-en-Provence
13/26 March 2009
day after Annunciation, N. S.