Treat multilingual technical SEO as a set of testable relationships between URLs, not as a one-time configuration task. Each check below should have captured evidence before remediation and a repeat crawl after remediation.
URL architecture check. Evidence required: a crawl export showing every indexable localized URL, its canonical, language, status code, and internal-link path. Pass condition: each intended language version has one stable, crawlable URL pattern and does not compete with an unnecessary duplicate.
Severity: high when conflicting versions are indexable. Owner: technical SEO lead with development support. Corrective action: standardize the chosen language structure and remove conflicting signals without changing useful URLs casually.
Validation: recrawl the affected templates and compare canonical, redirect, indexability, and internal-link outputs. Subdirectories such as example.com/fr/ can be practical, but the correct structure depends on the existing site, operating model, and migration risk. Tools: Google Search Console, Screaming Frog
Hreflang mapping check. Evidence required: a complete export of hreflang annotations for every localized page and its alternates. Pass condition: intended alternates use valid language or language-region values, reference the correct canonical pages, and return the relationship where required.
Severity: critical when the wrong market version is being surfaced or large groups of alternates are broken. Owner: technical SEO lead. Corrective action: repair missing, conflicting, or non-reciprocal mappings and keep the annotations aligned with canonical URLs.
The common translator SEO mistakes guide covers failure patterns that should be reviewed during this check. Tools: Hreflang Generator, Ahrefs
Performance and mobile template check. Evidence required: field data where available plus repeatable lab tests for representative localized templates. Pass condition: the localized templates do not introduce avoidable rendering, layout, or asset problems that are absent from the main version.
Severity: high when key service content is difficult to use or consistently slow for the intended audience. Owner: development or performance owner. Corrective action: reduce unnecessary scripts and asset weight, reserve layout space, and optimize media delivery. Validation: retest the same template set and document remaining limitations. Tools: PageSpeed Insights, WP Rocket
Localized XML discovery check. Evidence required: sitemap exports and crawl results for every intended indexable language version. Pass condition: sitemaps contain canonical, indexable URLs that resolve successfully and are consistent with the site's actual language architecture.
Severity: medium unless large portions of a market are undiscoverable. Owner: technical SEO lead. Corrective action: remove redirected, blocked, duplicate, or non-canonical entries and ensure useful localized pages are discoverable through internal links as well as sitemaps. Validation: resubmit where appropriate and compare subsequent crawl and indexing reports. Tools: Yoast SEO, Rank Math