One of the best things about the available textbooks of Hittite is that they preserve for the learner the uncertainty faced by a real scholar.  Our editions of Greek and Latin are "sanitized"--spellings and grammar match what we expect from our textbooks, not the more varied versions of the manuscripts.  Hittite is more fragmentary; there are very many unattested forms, and many variant spellings.  There are four forms given for the nominative plural of antuhsas, "man" (Hoffner and Melchert § 4.2); examples of ablauting verb stems are occasionally given alongside (variant?) forms that do not show the ablaut.  Moreover, there is a wide selection of verb endings for some of the numbers/persons, especially in the mediopassive.  A good challenge.