sin (2) adv., a form of sí "now" (q.v.) often occurring before vowels; also sín (SI). However, sí itself (q.v.) may also appear before a vowel.
Quenya
aite[?] kestallen
now, suppose, you ask me
aite[?] kestuvallen, tuluvanye
now supposing you asked me, a thing unlikely {or ridiculous} to suppose...
-itë
suffix. adjectival ending; [with verbs] capable of doing, generally (and naturally) doing
aitë
adjective. of any kind, of any sort
sin
now
sí
now
sí adv. "now" (Nam, RGEO:67, LR:47, SD:310, VT43:34, VT49:18, PE17:94), sin (SI, LR:47) or sín _(SD:247, 310) _before vowels. Compare the distribution of a/an in English, though in his Quenya version of Hail Mary, Tolkien used sí also before a vowel (sí ar "now and", VT43:28). Si, a short (or incompletely annotated) form of sí (VT43:26, 34). In Fíriel's Song, sí is translated "here".
sí
adverb. now
sí
adverb. now
The Quenya word for “now” which is very well attested. In notes on demonstratives from 1968, it is a vowel-lengthened form of demonstrative si “this” (VT49/18) which seems to be a standard way of forming adverbs of time in Tolkien’s later writings; compare tá “then” (VT49/11) and yá “when” (VT49/23). This vowel-lengthening construction was explicitly described in Demonstrative, Relative, and Correlative Stems (DRC) from 1948: “The bare stems lengthened are used [for adverbs of time]” (PE23/109).
In Tolkien’s writings from the 1930s and 40s, he occasionally had sin or sín “now” with an n (Ety/SIN; LR/47; SD/247; SD/310). One working theory is that this is the form of sí when it appears before a vowel. However, in the aforementioned DRC from 1948, Tolkien had a variant form ᴹQ. sin(an) “now” using the suffix ᴹQ. -n(an), also used for adverbs of time.
Conceptual Development: The Qenya Lexicon of the 1910s had ᴱQ. tyá “now” based on the early root ᴱ√KI “this by me” (QL/46, 49). In the Early Qenya Grammar (EQG) from the 1920s he had ᴱQ. qí or qin for adverbs of time based ᴱQ. qi “this”, hence = “✱now”. However, the untranslated text Sí Qente Feanor from the 1910s seems to use sí = “now” (PE15/32, 34).
Neo-Quenya: For purposes of Neo-Quenya, I would mostly use sí “now”, but I would also use sín or sin in cases where the results are more euphonic, particularly preceding a word starting with a vowel.
sír
adverb. now
A suffix for adjective formation, dating all the way back to Qenya Lexicon of the 1910s. When used with verbs, it has the more specific meaning “capable of doing, generally (and naturally) doing”, as in active cenítë “able to see” vs. passive cénima “visible, able to be seen”, both from cen- “to see”. The verbal use of this suffix was first described in the Quenya Verbal System (QVS) from 1948 (PE22/111), and was described again in Late Notes on Verb Structure (LVS) from 1969 (PE22/155).
When used with a verb, the suffix was preceded by the base vowel of the verb: i, e, a, o, u. This produced various diphthongs, and in the case of ei usually had [[q|[ei] becoming [ī]]]. The basic examples Tolkien gave were tirítë “watchful, vigilant, ✱apt to watch”, cenítë “able to see”, caraitë “active, busy, ✱apt to do”, coloitë “capable of bearing, tolerant (of), enduring”, and yuluitë “drinking (as a habit), ✱aquatic”.
Conceptual Development: As a general adjective suffix, there was a variant ᴱQ. -voite that was quite common in the Qenya Lexicon of the 1910s, also appearing in ᴹQ. hanuvoite “✱masculine” in The Etymologies of the 1930s (Ety/INI), but not thereafter. In Tolkien’s earlier writings, -itë had no specific verbal function, and ᴱQ. -alka, -elka, -olka was the suffix meaning “able to” in notes on The Qenya Verb Forms from the 1920s (VT14/33). This earlier verbal suffix also varied in form depending on the base vowel of the verb.