"Neh" is either a foreshortened loan of the French "n'est-ce pas?", or a direct loan of the Portuguese contraction "né?" (literally, "não é?"), which means the very same thing when placed at the end of a sentence. It is difficult to find any particular attribution to "neh" in English literature because it is vernacular and evolved as a spoken interjection, not to be written down.
- You are mostly correct, but Card isn't "inventing" Neh... his novels suppose a large influence of Portuguese upon the street vernacular, and given the time-line of the novels, he did so quite a while ago. -
"But the way I brain it," said the Launchy, "I be the best soldier I can, and any commander worth a damn, he take me. Neh?"
"Eh," said Ender, with finality.