I am aware. But the fragments of Hittite attested in these Old Babylonian texts predate the earliest bits of the extant Hittite corpus by about a century. Given

I am aware. But the fragments of Hittite attested in these Old Babylonian texts predate the earliest bits of the extant Hittite corpus by about a century. Given what we know about how the Hittite language evolved when it is well-attested, the differences are unlikely to be substantial. My point remains: If you want to study the earliest attested Indo-European language, there's a good freshman-level grammar out there.