Modeewine

<h4>What is «Polylang Theme Strings» and what for is it?</h4>
This plugin gives additional features to the plugin Polylang. It automatically scans all templates files and scripts of the active WP theme (and all plugins) for available strings that can be translated. For example:
<ul>
<li><code>pll__('...');</code></li>
<li><code>pll_e('...');</code></li>
</ul>
and adds them to the Polylang registery, after what you can manage the translation of finded strings using the administration panel. It will make your life easier for the development of multilanguage’s projects, because you will not need to enter the needed strings to translate manually – the plugin will do all the work for you. 
Don’t forget that in the example are described the PHP-function calls, that is why they have to be inside of PHP-tags.
<h4>How works «Polylang Theme Strings»?</h4>
You have to install the plugins «Polylang» and «Polylang Theme Strings» on your multilanguage WordPress CMS project and they must be both active. When you are in the settings of plugin (Polylang) in the tab «Strings translation» the «Polylang Theme Strings» scans automatically the active theme of your project, find all the code strings that needed to be translated, adds them to the register, displays them on that page and gives to user the ability to translate these strings.
Like you can see, the «Polylang Theme Strings» is perfectly integrate with the «Polylang» plugin and works in automatically mode – it is comfortable, simple, and useful!
From version 4.0 «Polylang Theme Strings» got settings page where you can configure the search strings-translations more deeply.
Learn more in <a href="http://modeewine.com/en-polylang-theme-strings" rel="nofollow ugc">http://modeewine.com/en-polylang-theme-strings</a>.

Polylang Theme Strings

I think there is a bug and it is changing the site language to english.

Works fine

Automatic scanning of strings translation in the theme and registration of them in Polylang plugin. Extension for Polylang plugin.

NicolasKulka

Amaury Balmer

Maxime Culea

BE API

Are you using Advanced Custom Fields for option pages and Polylang for your multilingual site?
Polylang does not natively support ACF Option Pages, so option values are shared across all languages. This plugin improves that: once activated, you can set different values per language. Values are stored per language in the database and the correct one is loaded according to the current Polylang language. If a value isn’t set for a language, the “All languages” value is used by default.
Note: On activation, existing option values become temporarily unavailable (but remain in the database); you can recover them by deactivating the plugin. To edit options for a language, use the Polylang language switcher in the admin bar before opening the options page.
Requirements: WordPress 6.0+, PHP 7.4–8.4, <a href="https://www.advancedcustomfields.com/pro" rel="nofollow ugc">Advanced Custom Fields</a> 5.6.0+, <a href="https://polylang.pro/" rel="nofollow ugc">Polylang</a> (tested up to 3.7.7).
For full documentation (usage, filters, API, excluding pages, default fallback, loading untranslated values), see the <a href="https://github.com/BeAPI/acf-options-for-polylang#readme" rel="nofollow ugc">project README on GitHub</a>.

ACF Options For Polylang

Improves Polylang by adding per-language support for ACF options pages—each language can have its own option values.

Polylang Theme Strings vs ACF Options For Polylang