Adding a language is not only a translation task. It changes navigation, content ownership, search targeting, forms, support expectations, and how updates are reviewed.
Decide what needs translating
Map the pages and journeys that each audience actually needs. A smaller set of complete, maintained pages is better than a large set of partial translations. Decide who reviews terminology and how new content enters the process.
Design for language differences
Allow for text expansion, different date and address formats, language attributes, clear language switching, and translated metadata where search visibility matters. Do not rely on flags as the only language label.
A well-defined website structure makes multilingual content easier to care for.