Many a character in many of my games has used quotations as dialogue. It's an innocent pleasure.
Favourites sources are plays, poems and lyrics but I'm not fussy.
Kyleth, the Witch Queen used a lot of Jacobean tragedy and Healaugh the halfling bard quoted Sondheim. The Moonlit King got a lot of the dottier bits of Walter de la Mare. A recent slaad was cursed with badly mangled bits of WWI poetry.
It's fun for me and a quick and dirty way to establish character. Palgrave sits on my desk and I have The Quote Garden bookmarked. As I say, an innocent pleasure.