In Shabbos 77a-77b, Chazal ask about the spelling of a series of words, questioning whether the words are spelled with an alef - as in גראינין - or with an ayin - as in גרעינין. Wasn't ayin vocalized ...
My research for my answer to Which alphabet were the original Torah scrolls in? gave me an idea--Since the Early Alphabetic alphabet is also called Sinaitic, and the timing seems about right, maybe ...
There is a tradition that the Alter Rebbe (R' Shneur Zalman of Liadi) innovated a new Ksav (not the one in the Shulchan Aruch Harav) and taught it to sofrim who passed it on from teacher to student. ...