Language configuration and translation assignment
Compare site languages, fallback behavior, and canonical of the invoked language version. A language prefix alone does not occupy any independent translated content.
Compare site languages, basic URLs, and the translations that actually exist. A detail extension must assign the same data sets and accessible paths as the output language references. Language fallback and real translation are not always the same content.
Where to check the setting in TYPO3
Control the languages of the site configuration and the translation relationship of the page or dataset. hreflang must match accessible language versions. A fallback output with unchanged content is not automatically an independent translation.
Example of this specific finding
Illustrative control case: An English performance page is called as a language alternative, but its canonical points to the German version. Translation and duplicate consolidation are contradictory.
follow-up audit in TYPO3
Open the other versions from each language version and check their canonical and reference back. Do not replace an empty or unavailable translation with a foreign homepage.
Maintain independent language versions with their respective matching canonical URL. Test language set and canonical goals together.
Derogations and scope
Almost identical regional sides of the same language may require a differentiated decision; different languages may not be combined in a blanket manner.
Reference: TYPO3 13.4 with EXT:seo. For other major versions and own extensions, responsibilities may differ; check the actually installed output.
Classify the general error
Definition, system-independent causes and further correction examples: Keeping translations and real duplicates apart