Quenya 

yanta-

verb. to add to, enlarge, increase, augment

@@@ possibly lyanta- if you accepted gy- > dy- > ly-

yanta-

verb. to join

A neologism coined by Paul Strack in 2018 specifically for Eldamo to be compatible with ᴺS. ianna-.

Quenya Group: Eldamo - neologism/reconstructions. Published by