Gnomish
luista-
verb. to be thirsty; to parch, dry up
luista nin
I am thirsty
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!
A verb in the Gnomish Lexicon of the 1910s which can be used transitively for “to parch, dry up” and impersonally to mean “I am thirsty”: luista nin (GL/55). It is based on the early root ᴱ√LOYO (QL/56).
Neo-Sindarin: For purposes of Neo-Sindarin, I would simply say ni faug for “I [am] thirsty” and would use ᴺS. [G.] thista- for “to dry up” (GL/73).