Why does the WordPress PDF use the wrong language on a multilingual site?

The output uses the wrong language when the plugin converts a different page than the translated page the visitor is viewing. Check how your multilingual plugin chooses the language, then match the plugin settings to that behavior.

If each language has its own public URL

If the translated page has its own URL, keep the Conversion Mode option set to URL.

If the output still uses the default-language page, set the URL Lookup option to Location. This tells the plugin to use the current browser URL, including the language path or query string, instead of the WordPress permalink. This is intended for translated URLs on the same site domain.

If the translated page depends on the visitor's current view

Some multilingual plugins or language switchers change the page after it loads. If the translated content is visible in the browser but the output still uses a different language, set Conversion Mode to Content.

Use Content when the converted output should match the page as the visitor sees it before clicking the button.

If the translated page is not publicly accessible

If the translated page requires a WordPress login, staging password, membership session, or another private-page condition, use the same approach as for other private WordPress pages: Can the plugin convert password-protected or private WordPress pages?.

Do not use Locale to select the translation

The Locale option controls regional formatting during conversion, such as date and number formatting. It does not choose the translated WordPress page.

If only the button label is in the wrong language

The button label is separate from the converted page content. Use the button translation FAQ when only the button text is wrong: How do I translate the Save as PDF button text on a multilingual WordPress site?.