Farksoo
Barbara Newhall Follett was a child prodigy who published two novels and wrote at least two other unpublished works all at a very young age. She vanished at the age of 25.
Among her artistic output is a constructed language called Farksoo which is spoken in her constructed world of Farksolia. Several fragments of Farksoo, as well as other things she has written, are available on a website dedicated to her work. In particular, the conlang can be seen here.
Some particularly lovely Farksoovian words:
treevaila -- to walk with great dignity
crys -- the nick of time; a trifle; a little thing; an unimportant matter; a pin prick
fileshai -- everything that is the opposite of crys
yrl -- anything that is light, fleeting and elusive
laeera -- to thread through a situation, circumstance, condition, difficulty or barrier, work it out, get through, pull through
vaida -- to go on any beautiful but materially useless journey or exploration; wander aimlessly, drift; hunt the snark; chase the stars and climb the sky; follow the horizon or catch the sunpath in the water; run away and play with butterflies; in the imperative, a polite and poetic remark of scorn on one's completely inefficient or ineffectual present action.
Of the grammar, we have this lovely bit of syntax: "There is a tense of wishing a thing might be, a sort of subjunctive, but untranslatable in English -- an elusive, ideal consummation, a dream highly improbable or even impossible of realization. That tense is formed by the suffix -ril to a verb. The dream of my life would be to go there: na oparil."