By default, WPML does not set the language cookie for site visitors that are not logged in. However, some themes and plugins need to run AJAX calls on the front-end, based on language information. For this purpose, you can manually enable a language cookie that supports AJAX filtering.
To enable language information for the front-end AJAX calls, go to the WPML -> Languages page and scroll down to the Language filtering for AJAX operations section. There, check the Store a language cookie to support language filtering for AJAX option.
This is how this works for visitors:
- For users that are logged-in, nothing changes and this setting is not applied. Language cookie is saved normally using PHP.