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.
Like all Elvish languages, the origin of Sindarin dates back to the Common Quenderin [CQ] language spoken by the Elves when they awoke beside the shores of Cuiviénen (S. Nen Echui). Even in those early days, the Elves divided themselves into three tribes, and Sindarin is ultimately derived from the dialect of the third tribe, later called the Teleri.
Sindarin was originally the native language of the Elves of Beleriand, but by the Third Age it was the language spoken by nearly all the Elves of western Middle Earth. As Tolkien described it in The Lord of the Rings Appendix F:
Of the Eldarin tongues two are found in this book: the High-elven or Quenya, and the Grey-elven or Sindarin ...