Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!

Qenya 

taita-

verb. to prolong, to prolong, *lengthen

A verb for “to prolong” in The Etymologies of the 1930s under the root ᴹ√TAY “extend, make long(er)” (Ety/TAY). For purposes of Neo-Quenya, I would also used it with the sense “✱lengthen”.