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 

yuyan(an)

adverb. on both occasions

A correlative combination in Demonstrative, Relative, and Correlative Stems (DRC) from 1948 (PE23/110), a combination of ᴹQ. yúya “both” and ᴹQ. -n(an) “occasions”.

Neo-Quenya: For purposes of Neo-Quenya I would stick to ᴹQ. yuyallume “✱both times”, since I think -n(an) was abandoned.