I would like to draw everyone's attention to a significant new
contribution to the linguistic and comparative study of the
phenomenon of vowel affection in Noldorin and Sindarin, made by
Bertrand Bellet (link is to an RTF file):
Bertrand's abstract:
"Vowel affection is a prominent phonological process in the
morphology of J. R. R. Tolkien’s Sindarin and Noldorin. This feature
appeared in the late stages of his Gnomish and remained in his series
of Welsh-inspired languages ever after. Its various kinds and the
terminology used to describe them are first introduced cross-
linguistically, with special reference to Celtic and Germanic
languages. Patterns of vowel alternations in Sindarin and Noldorin
from the Etymologies onwards are then examined synchronically: plural
formation, variation between related morphemes, alternations linked
to affixation and composition are successively considered. From these
data a model is elaborated to explain the diachronic development of
vowel affection, by means of comparison with Quenya and internal
reconstruction, as well as examination of Tolkien’s own indications.
The model includes five stages : lowering of high vowels by A-
metaphony, conditioned lowering of U to O, raising of mid vowels by I-
metaphony, fronting of back vowels by a later I-metaphony, and
finally breaking caused by palatalised consonants. In each case a
brief phonetic explanation is given with a list of relevant examples;
difficult cases and limits of the model are also discussed. Finally,
this reconstructed phonological history is compared to the
development of Welsh and the Germanic languages, in order to
appreciate how far Tolkien used them as models when he built his
languages."