Franz's education was spotty at best. He spent two years at the University of Kentucky, where he studied some Latin, but even less NT Greek. He left in 1914 after two years, because of becoming convinced that the world was to end in that year, courtesy of Russell.
As Hortensia has mentioned above, a vast mythology developed around Franz, encouraged, no doubt by the WTS. In the 50s a book entitled "Faith On The March" was published, written by WT heavy, AH MacMillan, which intimated that He spoke x number of languages, and was a stupendous scholar. Much of that was baloney.
He was no doubt an intelligent man, and possessed the one hallmark of scholarship that leads to erudition, a love of learning. His problem was that he rejoiced, vacuously, in the notion that he was, somehow a special "oracle" divinely appointed to plumb the depths of Scripture.
So he pursued the worst form of learning. He taught himself. He was "largely self-taught" in Hebrew and Greek.
The problem with being self-taught is twofold: 1You have a fool for a teacher 2 You isolate yourself from others who are in the same endeavour. There is something to be said for going through the crucible of testing that is called "exams" where you pit youself against your peers, and as result can tell where you really stand. Its nice to come first, but only when there are a second and third and so on. Coming first in a one horse race is an exercise in futility.
The only language endeavour I am aware of, is a course in Portugese, which Franz attempted to learn through a set of Linguaphone records. He wanted to do this because he was scheduled to make a trip to Brazil. Evidently his pronunciation was so bad, he was requested to give it a miss.
Remember, Franz had an almost open purse supplied by the WTS, which enabled him to purchase some of the finest works of Biblical learning that were available, books that would be beyond our price range. Using these, he was enabled, through diligent, but cultic inspired application, to construct his largely idiosyncratic "translation" of the Bile.
Nevertheless, his writing style was both cumbersome and prolix, and bordered on the unintelligible. His famous "Babylon the Great" must go down as probably the most incomprehensible book the WTS has yet produced. His "Life Everlasting In the Freedom of the Sons of God" published in 1966, was so impenertrable, that it was withdrawn from the weekly study after just six months since even the conductors found it hard to fathom its mysteries. A Random House editor commented that the book had to have been written by either a first year high school student of journalism, or an inmate in a mental institute. [Gruss - The 4 Presidents of the WTS, pg 42]
Despite living in a well populated centre such as Bethel HQ, Franz lived mostly in seclusion, and developed an egotistical, hermetically sealed outlook on life that was intolerant of any intrusive scrutiny.
But he was the best the WTS had, and with his passing, WT polemic has all but withered away, to be replaced by slick, legalistic mumbo-jumbo, mouthed by the new whiz kids on the WT block.
Cheers