S. adverbs grammar.
One notable feature of Sindarin is that it often uses adjectives adverbially, as in: noro lim, noro lim Asfaloth “run swift, run swift Asfaloth” (LotR/213). This can occur only when the adjective could conceivably be an attribute of the verb’s subject, as in this example where “swift” is applicable to the subject (Asfaloth). As Tolkien described it:
lim “quick, swift” (Q limbe < *lĭmbĭ); adjectival form is used when the quality of the action applies to the subject of verb immediately preceding, or to the subject expressed (as by a name) (PE17/18).
There are other examples where adjectives are put into prepositional phrases when used adverbially, notably cuio i Pheriain anann “may the Halflings live [for] long (an + and)” (LotR/953; Let/448). In this example a simple adjective cannot be used, because “long” is not applicable to the subject (the Halflings). David Salo suggested prefixal an- might generally convert adjectives to adverbs in his book Gateway to Sindarin (GS/140), but I suspect this is more properly a prepositional formation and the preposition used would depend on context.
Sindarin also has dedicated adverbs, such as mae “well”, palan “far”, sí “here”, hí “now”. It seems that where these modify the verb (as with adverbs of time and place) they may appear anywhere in the sentence depending on emphasis:
Where an adverb precedes a verb, it seems the verb is lenited. The best evidence for this is the negative adverbial particle ú in ú-chebin estel anim “I have kept (heb-) no hope for myself”. Where an adverb follows the verb, the evidence is more ambiguous. In the second example above, sí “here” was not lenited after the verb nallon. However, in the phrase edro hi ammen “open now for us” (LotR/307; PE17/45), it is likely that si “now” was lenited, at least when the phrase was first written.
In the Túrin Wrapper from the early 1950s, it seems the word “now” is sí, as in the phrase: sí il chem en i Naugrim en ir Ellath thor den ammen, untranslated but probably something like “*now all (?hands) of the Dwarves and Elves will be (?against) to us” (VT50/5). Likewise Q. sí is “now” in both The Etymologies of the 1930s (Ety/SI) and the Namárië poem (LotR/377). Thus it is probable that hi in edro hi ammen was lenited from unmutated si at the time it was written. However, later on Tolkien conceived of an alternate etymology for the Sindarin word for “now”, as hí < ✶khĭn- in notes from the late 1960s (VT49/34). This may have been an attempt to reconcile the inconsistencies in adverb lenition in The Lord of the Rings by deciding that hi was the unmutated form.
All in all, I think it is best to assume that adverbs following verbs are not lenited, so that “[he/she] spoke well” would be ebent mae (not vae). However, the evidence is mixed and I’ve seen some Neo-Sindarin writers who suggest such adverbs should be lenited.
As for adverbs modifying adjectives, based on the example o menel palan-diriel “from heaven far-gazing (tiriel)” (LotR/729; RGEO/64) it seems the adverbs precede and mutate adjectives; in this example it also forms a pseudo-compound. When modifying a noun, such pseudo compounds themselves probably undergo soft mutation, so that “the well made city” would be i ost vae-garnen (“well” = mae, “made” = carnen).
Conceptual Development: Tolkien only rarely wrote about adverbs for his languages. There is a mention of a discussion of adverbs in the Gnomish Grammar (GG/10), but if Tolkien ever wrote that section it did not survive.
Reference ✧ PE17/18 ✧ for example: noro lim, noro lim Asfaloth “run swift, run swift, Asfaloth”