Google Ads has officially removed language targeting settings for Search campaigns. As announced in August, advertisers must now rely on their ad copy and landing pages to match users by language, as the setting is no longer available.
The change also affects Performance Max campaigns, where language settings will no longer apply to ads shown on the Google Search Network. However, the settings will continue to be relevant for other channels like YouTube and Display.

Advertisers are advised to continue separating campaigns by language for better budget control and reporting, while ensuring not to mix languages within a single ad group.
This update was shared by Thomas Eccel.