Explanation
Two options that could be recommended for localizing email content to speak to subscribers in their own language are:
Leverage AMPscript within an email template to lookup subscriber language and personalize the email based on the value. AMPscript is a scripting language that allows marketers to perform complex tasks within messages, such as looking up data from data extensions, applying conditional logic, or displaying dynamic content based on subscriber attributes or behaviors.
Leverage enhanced dynamic content blocks within Content Builder to create language-specific emails.
Enhanced dynamic content blocks are blocks that allow marketers to create personalized content based on rules and filters without coding.
Leveraging personalization strings within the email template will not help with localization, as they are used for inserting simple subscriber attributes or system information into messages. Leveraging Content Builder to create email templates for each individual language will not be efficient or scalable, as it will require creating and maintaining multiple templates for each message. References:
https://help.salesforce.com/s/articleView?id=sf.mc_es_ampscript_overview.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.mc_ceb_enhanced_dynamic_content_blocks.htm&type=5