In Quenya you (thou, thee, you; formal/polite 2nd person singular) is lye or elyë or the pronominal ending -lyë.
In Quenya you (you, thou, thee; intimate/familar 2nd person singular) is tye or the pronominal ending -tyë.
This word got me into some Quenya grammar. I know about formal and informal versions of you, from Spanish. But pronominal suffixes?!?
I didn't find a Sindarin word for you or thou.