The Pali text is not the only Dhammapada, and the others are the strongest evidence for what kind of thing it is. A Gandhari version, written in Kharosthi script on birch bark from the region of modern north-west Pakistan and Afghanistan, is among the oldest Buddhist manuscripts known; it has twenty-six chapters, several of them fragmentary, but its chapter titles and its ordering differ from the Pali. A manuscript found at Patna preserves another recension in a Prakrit closer to Sanskrit, with twenty-two chapters and 414 verses. The Sanskrit Udanavarga, associated with the Sarvastivada school and preserved in Central Asian fragments as well as in Tibetan and Chinese translation, is much larger: thirty-three chapters and around a thousand verses in the standard edition.
Comparing them, John Brough found the recensions share in the order of 330 to 340 verses and sixteen chapter headings, along with an underlying structural pattern. That is the useful fact. No version is a translation of another, and none is plausibly the original. What existed was a circulating body of memorised didactic verse, drawn on by several schools, each of which selected, arranged and titled its own anthology. The Pali collection is one such settlement of that material, made within the Theravada lineage, and its authority in that tradition does not depend on it being first.
The word itself carries the ambiguity. Dhammapada can be read as the path of dhamma, or as verses of dhamma, dhamma here meaning the Buddha's teaching and pada meaning foot, step, path, or line of verse. Both readings are old and both are defensible, and translators have gone either way.