Sindarin 

eithro

adverb. *also

The Gnomish Lexicon of the 1910s had G. arthi “also, as well, besides, too”, related to G. ar “and” (GL/20). In the Gnomish Lexicon Slips modifying that document, it became erthi “also, as well” after Tolkien introduced i-affection to the language (PE13/113). Years later, Tolkien had a similar form eithro in the Túrin Wrapper of the early 1950s (VT50/5), possibly still meaning “also” as suggested by Carl Hostetter (VT50/12), appearing in the (untranslated) phrase i·Veleglind i eithro en estar i·Chîn Húrin “✱the Great Song that is also called the Children of Húrin”.

Neo-Sindarin: Since the etymology and meaning of eithro is rather unclear, Elaran suggested ᴺS. aich “also” < ✱as-jē as an alterative, connected to S. a(h) “and” < √AS. Personally I lean towards attested eithro, but given its obscurity aich “also” is a viable alterative.

i·veleglind i eithro en estar i·chîn húrin

*the Great Song that is also called the Children of Húrin