How to deal with the large number of duplicate pages (Duplicate) in GSC after opening multilingualism?

Hi Qin Evening Rong, it's very common to see duplicate pages in GSC for multi-language sites, often because Google hasn't yet recognized the relationship between the language versions of the "main page" clearly. Here's how to solve the problem 👇. ✅ 1) Canonical: each language page is "self-canonical", each language page canonical to itself (self-canonical). Don't canonicalize all languages to the main language (this makes Google think that other languages are just duplicates/alternatives). Suggest to go to GSC "URL Check" and read two lines: User-declared canonical vs. Google-selected canonical. If Google keeps selecting the wrong one, it's usually an in-site link, sitemap or redirect that's "pulling the rug out from under you". 🌍 2) Hreflang: complete, bi-directional, occurring in groups (don't miss), same group of languages pointing to each other: A points to B, B points back to A (bi-directional) Each version should contain all languages in the group, x-default is recommended (especially clear if there is a language selection page or default page) Common pit ⚠️: caching/CDN caches hreflang into a certain language version, resulting in inconsistent output for other language pages. 🗺️ 3) Sitemap: language independent is clearer and must be consistent. Option A (more recommended): separate sitemap for each language /sitemap-en.xml, /sitemap-zh.xml The URL in the sitemap must be canonical to the page. Option B: a sitemap can also be, but to ensure that the URL with canonical, hreflang logical consistency Key: Don't have a sitemap that puts URL A, but the canonical points to URL B. This creates a direct Duplicate. 🧹 4) Parameter page / language switch parameter: unified treatment (most likely to burst Duplicate) If you have these forms: ?lang=en, ?currency=USD, ?v=xxx, utm_ Parameter Page Suggestion: ✅ noindex This type of parameter page ✅ canonical points to "clean URLs" (official language URLs without parameters) ✅ Do-what-you-can rule: put ?lang= 301 to path versions like /en/ (more thorough). 🔗 5) Content and internal links: don't "mechanically copy", close the loop within languages Try to "translate/localize" the content of different language pages, don't just change one or two sentences. Title/H1/first paragraph/FAQ: It will be more natural to do some language differences. Link to each other in the same language as possible (English page links to English page, Chinese page links to Chinese page) Menu, breadcrumbs, related articles, product recommendations, it is also best to do the language version of the corresponding 🔍 6) Duplicate types you should prioritize (by importance) In GSC, the meaning of the following two is much worse: ✅ Alternate page with proper canonical tag It means that you declared it clearly, which is usually not a big problem ⚠️ Duplicate, Google chose different canonical than user This is what you need to focus on (it means Google doesn't believe in your canonical settings) ⏳ 7) Don't rush, it takes time When a multilingual structure first goes live, GSC tends to have more Duplicates for a while. As long as you align the canonical / hreflang / sitemap / parameter pages, it usually goes down gradually and the indexing and ranking can stabilize.