The LotR is feigned to be a translation from the Red book, and English represents Westron in the "original". And when a foreign word appears in the texts, I believe Tolkien meant the "authors" were using it, or recording it.

Now, since the books call it Pelennor, the fields of Pelennor, the field(?)*, etc.. I imagine these names were what the "authors" (Bilbo, Frodo, etc.) and the characters (mostly Westron speakers) used, with the English part replaced by Westron.

It shouldn't be a surprise, because we are told that Gondorians did use Elvish (mainly Sindarin) for place names, even if not all of them could use it for daily speech.

Yet the names of nearly all places and persons in the realm of Gondor were of Elvish form and meaning. - Appendix F.

* Denethor said "you may triumph on the field, for a day", but later Gandalf rephrased it to be "You may triumph on the fields of the Pelennor for a day". It's possible "the field" was understood to be Pelennor, at least for the residents of Minas Tirith.

The LotR is feigned to be a translation from the Red book, and English represents Westron in the "original". And when a foreign word appears in the texts, I believe Tolkien meant the "authors" were using it, or recording it. For example, Rivendell (English/Westron) and Imladris (Sindarin) are used by different characters for different situations. The Hobbits understandably tend to use the Westron name.

Now, since the books call it Pelennor, the fields of Pelennor, the field(?)*, etc.. I imagine these names were what the "authors" (Bilbo, Frodo, etc.) and the characters (mostly Westron speakers) used, with the English part replaced by Westron.

It shouldn't be a surprise, because we are told that Gondorians did use Elvish (mainly Sindarin) for place names, even if not all of them could use it for daily speech.

Yet the names of nearly all places and persons in the realm of Gondor were of Elvish form and meaning. - Appendix F.

* Denethor said "you may triumph on the field, for a day", but later Gandalf rephrased it to be "You may triumph on the fields of the Pelennor for a day". It's possible "the field" was understood to be Pelennor, at least for the residents of Minas Tirith.

The LotR is feigned to be a translation from the Red book, and English represents Westron in the "original". And when a foreign word appears in the texts, I believe Tolkien meant the "authors" were using it, or recording it.

Now, since the books call it Pelennor, the fields of Pelennor, the field(?), etc.. I imagine these names were what the authors(Bilbo, Frodo, etc.) and the characters (mostly Westron speakers) used, with the English part replaced by Westron.

It shouldn't be a surprise, because we are told that Gondorians did use Elvish (mainly Sindarin) for place names, even if not all of them could use it for daily speech.

Yet the names of nearly all places and persons in the realm of Gondor were of Elvish form and meaning. - Appendix F.

The LotR is feigned to be a translation from the Red book, and English represents Westron in the "original". And when a foreign word appears in the texts, I believe Tolkien meant the "authors" were using it, or recording it.

Now, since the books call it Pelennor, the fields of Pelennor, the field(?)*, etc.. I imagine these names were what the "authors" (Bilbo, Frodo, etc.) and the characters (mostly Westron speakers) used, with the English part replaced by Westron.

It shouldn't be a surprise, because we are told that Gondorians did use Elvish (mainly Sindarin) for place names, even if not all of them could use it for daily speech.

Yet the names of nearly all places and persons in the realm of Gondor were of Elvish form and meaning. - Appendix F.

* Denethor said "you may triumph on the field, for a day", but later Gandalf rephrased it to be "You may triumph on the fields of the Pelennor for a day". It's possible "the field" was understood to be Pelennor, at least for the residents of Minas Tirith.