How does Frodo write in English?

There's a scene at the ending of "Lord of the Rings - Return of the King", where Frodo appers finishing writing a book called "Lord of the Rings"... in plain English! This kind of broke down my suspension of disbelief.

We see Elvish and Orc languages all over the trilogy. Are we actually supposed to expect the Hobbits to used a modern language at that time/universe?

(There's also at least one English written plaque in the Desolation of Smaug introductory scene, naming the village where the action is taking place)

I'm ok with them all "speaking English" because I can just imagine the movie was "dubbed into English" from whatever language the characters have been actually using (just like I do with Star Wars, Amadeus or The Last Temptation of Christ, just to name a few). But seeing books with English felt like seeing a hobbit using a watch or holding a can of soda.

p.s.: While I have not read the book, I did read Silmarillion, that explains the origin of them all, and I can't manage to fit the West Germanic medieval language into their culture.

Best Answer

This is not just particular to the movies, but also to the books. Tolkien intentionally chose to translate and transliterate Westron to English. From the Tolkien Gateway:

According to Tolkien's fiction, Westron was the language spoken and understood by the protagonists of The Hobbit and The Lord of the Rings. Many names of characters and places, in the book's "reality", were in Westron.

However, Tolkien mentions that Westron was presented as having been completely replaced by English in the text. This had certain important implications: first of all, proper names with derivations understandable or evident to speakers of Westron had been translated, to preserve the effect to the English reader. Thus, names like Baggins, Bagshot Row, Peregrin, Rivendell et cetera, are not the actual names as spoken by the characters but are presented as translations.

Of course, outside the fictional context of the story, it is clear that there was no such "translation": the English names came first and the "original" forms in Westron or other languages were devised by Tolkien later.

Rivendell ("cloven valley") was actually called Karningul, and Bag End was actually called Labin-nec, after Labingi, the real form of Baggins. In some cases the explanations became quite involved, such as the river Brandywine (Sindarin Baranduin, "golden-brown river") was actually called Branda-nîn, a punning Westron name meaning "border-water", which was later punned again as Bralda-hîm meaning "heady ale".

This logic went one step further by also presenting all Mannish languages akin to Westron in languages related to English, so that their "understandability" by the protagonists be simulated to the English reader.

This utter replacement of Westron by English was taken so far that some sources that should give actual Westron have been turned to English too. For instance, in Moria, an illustration of the runic text on Balin's gravestone is given. The text is said to be written in both Khuzdûl and Westron. But while the first part of the inscription seems to really be a bit of Khuzdûl, the second part is actually plain English, just written in cirth.