[Hittite nouns in -a that denote the end of motion are not locatives but sentence doublets. They come partly from accusatives in -an, and in part parallel the dative-locatives in -i, which (cf. Engl. where, here, there) had come to express the end of motion. The dative-locatives in -i and those in -a both continue PIE cases that ended in an i-diphthong. The forms were originally conditioned by the initial sound of the following word. Subsequently the analogic extension of the -a form was favored in expressions of the end of motion by the fact that this was the only function common to the accusative and the dative-locative.
The construction is particularly frequent in proper names; and as the form resembles Babylonian proper names, the result has been the constant appearance of Hittite proper nouns in Accadian texts under what seems to be the form of their stem.]