Historical context
After the Flight of the Noldor, the Noldor and the Sindar began to find a medium of communication with one another. In learning one another's languages, the Noldor caught quickly onto Sindarin, while the Sindar had extreme difficulty with Noldorin (Quenya). This was the first step towards Sindarinization.
The next step came quickly and absolutely. Elu Thingol learned of the Kinslaying at Alqualondë, and was horrified and angered at the massacre of his kin. He declared that the tongue of the kinslayers would not be spoken in his hearing, and commanded all Sindar not to speak it or answer to it, and to shun those who spoke it. Therefore the Noldor were forced to speak Sindarin, and it became their tongue in daily use. Quenya stayed still in their lorebooks, and was spoken in private among the lords of their kindred.
- Feanáro > Feanor[note 1]
- Curufinwe > Curufin
- Finwe Ñolofinwë > Fingolfin
- Arakáno > Argon
- Findekáno > Fingon
- Finwe Arafinwë > Finarfin[note 2]
- Ingalaure > Inglor (see: Gildor Inglorion)
- Ambarussa > Amras, Amros[note 3]
- Makalaure > Maglor
- Maitimo Russandol > Maedhros
- Tyelkormo > Celegorm
- Carnistir > Caranthir
- Angaráto > Angrod
- Aikanáro > Aegnor
- Turukáno > Turgon
- Itarillë > Idril
- Findaráto > Finrod
- Alatarielle > Galadriel[note 4]
- Eärendil > Aerendil, Aerennel
 Other versions of the Legendarium
In the earliest versions of the mythology (as narrated in The Book of Lost Tales), the process why the Noldoli wore such names is quite different: The Noldoli spoke Old Noldorin in Valinor, a language similar to Qenya, and upon their arrival to Beleriand, their language was much influenced by the vernacular Celtic-like Ilkorin, and evolved to an amalgamated language, Noldorin. These classical character names were originally envisioned as Noldorin by Tolkien.
In the latest phase of writing, the relationship between Quenya and Sindarin changed drastically. Tolkien however retained the "Noldorin" names he was always using, and attributed them to Sindarization.
- ↑ Said by Helge Fauskanger in his article on Sindarin to be "a compromise between pure Quenya Fëanáro and the 'correct' Sindarin form Faenor".
- ↑ Finarfin is perhaps unique in being known primarily by his Sindarin name despite never reaching Beleriand.
- ↑ In The Problem of Ros Tolkien considered whether Amros would be more correct, but he didn't seem to stick on this name.
- ↑ Fauskanger (ibid.) notes that this example is more elaborate and a correct translation, in contrast to simple sound change.