The stores often have multiple views for different languages. The Amasty extensions are easy to translate using the following article - How to translate a Magento 2 extension?
However, there are peculiarities associated with the translation of the Advanced Search popup, since the translations of the JS files are stored in the js-translation.json file located in
pub/static/frontend/*theme_vendor*/*theme_name*/*locale_name*/js-translation.json
If the Magento operation mode is set to Developer, this file is generated only when it doesn’t exist in the static files. In the Production mode, the file is not changed even after changing translations in locale_locale.csv files and flushing the cache. In this regard there is a number of additional steps to be followed after modifying the files in the i18n directory:
1. In the Developer mode, it will be enough to delete the js-translation.json file and clean the cache.
2. In the Production mode, it is required to regenerate static content. This can be achieved by executing the following commands in CLI from the Magento root directory:
rm -rf pub/static/*
php bin/magento set:static-content:deploy
php bin/magento cache:flush