My theme or some plugin is not translated

There are two main reasons for this to occur:

1. Your theme or plugin may not be translated (no or incomplete .po/.mo files). You can use poedit the plugin Loco translate to make the translation.
2. Your theme or plugin may not be compatible with the Polylang option “The language is set from content”. Try using the default setting: “The language is set from the directory name in pretty permalinks“.

Read also Loco Translate, the right complement to Polylang