Listify is translated in to many different languages! If your language has translated 75% or more of the strings in Listify the language files will automatically be packaged with Listify. This means if you have WordPress set to use your language they will be applied automatically.
If your language is still not being applied, you may need to rename the language files depending on your locale. For example, by default the French translation ships as simply fr.mo and fr.po. WordPress requires a country code and locale for language files so if you simply need pure French, you can rename them to fr_FR.po and fr_FR.mo
Contribute Your Translation to The Theme Core Files
Core translations are hosted on Transifex. Anyone can sign-up and start translating here and any updates will be included in the Listify theme updates.