With Poedit you can edit popups.po that is located in the languages folder of the plugin. Once translated save it into the languages folder and rename both .po and .mo to the translated language appeding spu- to it.
For example if you translated the plugin into spanish, save it as spu-es_ES.mo and spu-es_ES.po and put that files inside the language folder.
Please contribute with the plugin and send us your translation files