[cëa, cëan ("k") cardinal "ten", forms Tolkien later abandoned in favour of quain or quëan. An adjectival form caina ("k") was also listed, but must likewise be considered obsolete. (VT48:12-13, VT49:54)]
Quenya
cëa(n)
cardinal. ten
cainen
cardinal. ten
cainen
cardinal. ten
cëa
cardinal. ten
quain
cardinal. ten
quain cardinal "ten" (also quëan); quainëa ordinal "tenth" (VT48:6, 20; VT42:25). Quain or quëan replaced the form cainen in Tolkiens conception.
quain
cardinal. ten
quëan
cardinal. ten
quëan cardinal "ten", also quain (VT48:6, 12, 20). Quain or quëan replaced the form cainen in Tolkiens conception.
quëan
cardinal. ten
Eldarinwe Leperi are Notessi (ELN) from 1968 had the words quëan and quain for “ten” (VT48/6). The latter was used in adjectival quainëa “tenth” (VT42/25), and on this basis I believe quain is the form used in compounds, while quëan is its form as an independent word. Its primitive form is ✶kwayam based on the root √kwaya originally referring to the whole (√KWA) set of ten fingers (VT42/24).
Conceptual Development: Tolkien introduced this word for “ten” fairly late in his life. In the Qenya Lexicon of the 1910s the word for “ten” was ᴱQ. lempe, related to ᴱQ. lemin “five” and appearing under the early root ᴱ√LEH [LEǶE] (QL/52). In the Early Qenya Grammar (EQG) of the 1920s, the base word for “ten” was ᴱQ. kai, already referring to the ten fingers (PE14/51, 84). In combination with other numbers it used its partitive form ᴱQ. kainen “ten” as in ᴱQ. yukainen “twenty” = “✱two of ten”, ᴱQ. otsokainen “seventy” = “✱seven of ten”, and so forth (PE14/49, 82-83). It had an adjectival variant ᴱQ. kea also used in the “teen” numbers: ᴱQ. kankea “fourteen” (PE14/49, 82).
In The Etymologies of the 1930s the partitive form became the normal form ᴹQ. kainen “ten” under root ᴹ√KAYAN of the same meaning (Ety/KAYAN). The form cainen “ten” continued to appear in Tolkien’s later writings (PE17/95; CPT/1296) along with a shorter form cëa. This short form kea(n) appeared in rough notes associated with ELN from 1968, replacing kainen to avoid confusion with cainen “I lay”. Ultimately in this document Tolkien settled on quëan/quain as mentioned above.
Neo-Quenya: For purposes of Neo-Quenya, I use quëan “ten” as an independent word and quain in compounds such as ᴺQ. yuquain “twenty” = “two tens”.
[cainen] ("k") cardinal "ten" (KAYAN/KAYAR). According to VT48:12, Tolkien eventually rejected this word (cainen would only mean "I lay", sc. the pa.t. cainë with the ending -n "I"). See quain, quëan.