Sibilant mutation results from an ancient preceding s that was caused various mutation effects before being lost. The two best examples of sibilant mutation are the preposition o “about” and (possibly) the conjunction a “and”. The most complete description of sibilant mutation appears in a discussion of one of the etymologies of “and”:
Liquid mutation results from a preceding liquid r, l. This is a rather speculative mutation, based only a couple of examples and what we know about Sindarin’s phonetic history. The only examples of liquid mutation appear in a couple of phrases from a document referred to as the Túrin Wrapper (VT50/5):
Stop mutation results from a preceding (ancient) voiced or voiceless stop t and d, generally from a preceding preposition. This stop is typically lost before consonants with various mutational effects. This is a somewhat speculative mutation, since Tolkien described it but we have no actual examples of this mutation in an attested sentences, except for in one rejected note where Tolkien considered making na-chaered stop mutation rather than soft mutation (PE17/147, where he described it as being from nat- or nad-).
One interesting feature of Sindarin is that its nasal mutations are distinct from those of Welsh. In particular, the nasal mutations of p, t, c are ph, th, ch rather than voiceless nasals “mh, nh, ngh” as in Welsh. This is especially peculiar given that Sindarin mostly underwent the same medial phonetic developments as Welsh, whereby (for example) nt > nth > nnh (long voiceless nasal) > nn.
This entry skips a couple of small “bridge” entries which is why the part number jumps to 10.
Sindarin soft mutation is pervasive in the language and serves numerous functions: marking the direct object of a verb, the modified form of a noun following an article, the modified form of an adjective following a noun, etc. This entry primarily discusses the mutational process itself. The conditions under which mutations occur is addressed in other entries.
Sindarin is primarily a SVO language (subject-verb-object), with subject first, followed by the verb and then any objects of the verb. In many situations, Sindarin has a word order similar to English: the subject precedes the verb, prepositions precedes the qualified noun phrase, relative pronouns precedes the subordinate clause, etc. One major exception to this rule, however, is that Sindarin adjectives follow rather than precede their noun:
Tolkien described the basic Sindarin stress patterns in the The Lord of the Rings Appendix E (LotR/1116), and they are essentially the same as for Quenya (and Latin): stress falls on heavy syllable closest to the end of the word, except (a) it cannot fall on the last syllable of polysyllables and (b) cannot be further back than the third-to-last syllable. A syllable is “light” if has a short vowel and ends in no more than one consonant; it is “heavy” if it has a long vowel, a diphthong or ends in more than one consonant. Thus:
Sindarin’s consonant and vowel inventory is described in The Lord of the Rings Appendix E, at least indirectly (LotR/1113-1116). The Sindarin consonants of the 1950s-60s are almost the same as the Noldorin consonants of the 1930s appearing in the Comparative Tables of linguistic development from the 1930s (PE19/18-23), excluding only hw which in Noldorin was chw.