Using a file browser, I am able to look at the SD card and see that /storage/extSdCard/Android/data/com.google.android.apps.translate/files/olpv3/v5/25/r11 contains folders like dict.en_pt_25, lang.en_pt, and lang.pt_en where "pt" is also replaced by some other two-letter language codes. .../r12 contains the files for French.
In the file browser, at e.g. .../r11, Select All and choose Move, and move them to the similar path on internal memory (which works out to be /storage/emulated/0/Android/data/com.google.android.apps.translate/files/olpv3/v5/25/r11) and also move the other revisions (e.g. .../r12 on the SD card to .../r12 on internal memory). The app itself can still be running on the SD card, but for some reason it can't find the offline translation files there.
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