DISCLAIMER: This article is preliminary research on the part of its author (Paul Strack) and does not necessarily reflect the opinions of the owner of this site. Since the source material is complex and its interpretation can be subjective, multiple conclusions are possible.
I’m posting this introductory entry out of order, because I want to write up the entries on the individual consonant mutations before writing an overview.
Sindarin has a number of consonant mutations with various effects. Tolkien said:
The lenitions or “mutations” of S. were deliberately devised to resemble those of W[elsh] in phonetic origin and grammatical use; but are not the same in either p[honetic] o[rigin] or g[rammatical] u[se] … [in a footnote] though of phonetic origin, they are used grammatically, and so may occur or be absent in cases where this is not phonetically justified by descent (from a 1972 letter to Richard Jeffrey, Let/426).
Indeed, the two most frequent Sindarin consonant mutations are soft mutation and nasal mutation, and both bear a strong resemblance to the corresponding mutations in Welsh but differ in a few particulars. The principle effect of mutations is the modification of a following consonant, which typically undergoes sound changes similar to its historical medial development under the influence of a closely preceding word or clitic.
Of the Sindarin mutations, the best understood are:
- The soft mutation which is the result of a (often vanished) preceding vowel.
- The nasal mutation which is the result of a (often vanished) preceding n.
- The mixed mutation which is a mixture of soft and nasal mutation.
Soft mutation is the one that is most “grammaticalized” and is introduced into a number of contexts where it could not be the result of historical sound changes. One example given by Tolkien:
palan-tîriel [which appears in LotR as soft mutated palan-díriel] should phonetically > -thíriel, past participle “having gazed afar”; but grammatically before actual forms of verbs, the soft mutation only was normally used in later S., to avoid the confusion with other verb stems (ibid., Let/427).
In this context, the soft mutation is probably the result of an adverb preceding a verbal form: “far (palan) having-gazed (tíriel)”. It is used as a grammatical mutation rather than the nasal mutation that would result from purely phonological changes. In her book A Fan’s Guide to Neo-Sindarin, Fiona Jallings reserves the term “lenition” (strictly speaking just another term for “soft mutation”) for soft mutations that are grammatical rather than phonological in nature, and I have adopted this convention as well.
There are three other Sindarin mutations that are less understood and are to some degree speculative:
- The stop mutation which is the result of a preceding stop d or t.
- The liquid mutation which is the result of a preceding liquid l, r.
- The sibilant mutation which is the result of a (lost) preceding sibilant s.
Compared to other mutations, they are obscure and poorly attested and may or may not have been a regular feature of Sindarin as Tolkien conceived of it. Of these, stop mutation has the best support and is mentioned in several places. Sibilant mutation is described in only a single source, and has no clearly attested examples or counter examples. Liquid mutation is not described in any published source, examples of it appear in only a single source, and a several counter examples appear elsewhere. In terms of how likely they are to be part of Sindarin, I would rank them (for most to least likely) as stop, sibilant, then liquid, but all three can probably be ignored in Neo-Sindarin writing as they arise relatively rarely.
As a final note, some mutations also modify the preceding consonant as well as the following consonant. This is most notable in nasal, mixed and stop mutations, where the preceding n or d may also undergo changes, vanishing or being modified along with (or instead of) the following consonant.