"Wise and learned in the scrolls of lore and song, and yet a man of hardihood and swift judgement in the field. Less reckless and eager than Boromir, but no less resolute."
First of all, we prefer the term 'language'.
And it depends on your personal style which of the two best suits you.
Sindarin is like the Celtic languages and has lots of mutations, the structure of Quenya is like Latin or the Finno-Ugric languages and so has many cases.