Translating a React app involves more than wrapping strings in t()

A developer found that using an AI agent to internationalize a side project required reading every changed file to verify its choices, which prompted a more careful approach. Plural rules are a major pitfall: English needs two forms, but Russian needs four, and missing plural keys cause fallbacks to English or missing-key text. Machine translation can also corrupt placeholders such as {{name}}, so translations should be validated against the source for matching placeholders and counts. Inline markup like links needs to be preserved as numbered tags so translators can reorder text without breaking the structure. Non-translatable strings such as CSS classes, URLs, and brand names must be excluded, and variants like Simplified and Traditional Chinese need separate handling.