Based on #1498634: [meta] Define revision/translation SQL schema for core entities (no patch) there should be a new schema. The name should be comment_translation it's connected to comment directly.
Retitle based on #1658712: Refactor test_entity schema to be multilingual. Marking postponed on #1691952: Make EntityFieldQuery work with multilingual properties.
Comments are converted to Entity NG, so this should be fully possible now.
Tagging for D8MI.
Following here to have less collisions with #731724: Convert comment settings into a field to make them work with CMI and non-node entities
Also related #2028025: Expand CommentInterface to provide methods
...related issues have a special, dedicated place after the d.o D7 upgrade ;)
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