OK, back from work and class, so I can address this more fully.
Narnia is unrealistic. Forget about magic wardrobes, centaurs, and satyrs. I'm talking about other things. For example, why does everyone in Narnia speak English
? This clearly contradicts a passage in PC which said that nobody could read the text in Aslan's How. If Narnia's language changed by the time of PC, why would the Pevensies understand Narnian? Secondly, why did Aslan create Narnia to be geocentric? That is VERY unstable. Is that the reason why Narnia only lasted less than 3000 years? Last but not least, why are there no technological advances in Narnia? I mean, at the beginning of Narnia weapons and buildings were somewhat medieval. That corresponds to about 900AD in our world. In Prince Caspian technology should have advanced to about 2900 AD in our world which means starships and guns. But in Narnia it stays the same: swords, daggers, maces, axes.................
I've already explained why Narnians speak English -- Aslan brought the first settlers from England. However, this doesn't explain why Narnian English is exactly the same as ours. In the centuries that Narnia existed, the language ought to have changed and developed some. It can't be influenced by other languages, because English is the only one Narnia has, but it should still grow. People should still be coining words, word definitions should still be changing. That's just the nature of a living language. The text in Aslan's How, IIRC, was the ancient runic language on the Stone Table, which nobody in Narnia could read. It's from before Narnia's time.
As to why Narnia is geocentric...well, why not? It's a fantasy realm. As long as Lewis didn't write anything that would contradict the physics of a flat, geocentric planet, it's fine. (I can't say whether or not he did, as I know nothing about such things.)
Technology: First off, Narnia is less than 3000 years old, and it didn't start in the height of medieval technology. Frank and Helen were very simple people, even if they did come from a more advanced era. I doubt they had the education or ambition to continue advancing technology, or even to recreate what they knew of it, so Narnia was essentially starting over from scratch. As others pointed out, technological has only advanced really rapidly within the last century or so in our world, and it's much older than Narnia. Yes, the Telmarines came in later, and they may have had technology, but it's hard to say when in Earth time they were from, or even how much technology they had at the time. They were shipwreck fugitives, so I doubt they had much technology either, and even if they had a few guns on them, they'd have to have someone with the education and ability to replicate them.
Additionally, Lewis was playing off an old literary trope with his Narnia stories, by making them all take place in a medieval-esque world. He was playing off the nostalgic idea that things were better during the medieval period, that men were braver and women were more virtuous, and that the world was a more romantic place. He's not the first author to do so; there was a renewed interest in the Arthurian romances around the 19th century. By following in this tradition, Lewis was ensuring that Narnia would be viewed as a charmed, idealistic world that the children would always want to return to. And, if we look at what he wrote about Eustace's progressive, modern family and school, Lewis didn't seem to be in favor of progress for the sake of progress.
Don't be so technical.I like it the way it is.IT'S FICTION,FOR PETE"S SAKE!!!!
Oh, the "It's fiction!" excuse. I see this everywhere when discussing fantasy worldbuilding, and it just doesn't cut it. Yes, you can get away with some things because of fiction (dwarves, satyrs, nature spirits, etc. existing), but you can't use it to explain everything away. A fantasy world still has to retain internal logic or risk severe criticism, so Prince_Caspian's questions are entirely valid. How HAS a world existed for two millenia without the language changing even a little? It doesn't make sense. My own personal belief is that Lewis just ignored the question as he didn't find it relevant to his purpose. After all, as JRRT's best friend, one can hardly assume him to be ignorant on the subject of linguistics.
Most observant readers of the Narnia books know that they lack consistency in multiple areas, both in terms of worldbuilding and in continuity (oh, the continuity errors surrounding Jadis and her backstory!). I generally try not to let those bother me, because I think the stories themselves are good enough to warrant a bit of selective blindness in those areas. However, they are very valid questions to raise and make for interesting discussions.
