The highlighted comment was created in this revision.
Please remove Template:Welcome/i18n temporarily from translation and move the existing translations to its subpages. (You can re-add it after all translations have been moved.) Then they should be merged into the translation system – this is the part in which I can help, or you can use Special:PageMigration. This complies with copyright while making the migration easier (especially if you chose PageMigration). Thanks,
I intentionally avoided doing so, to have the old subpages around and quickly restorable. If you copy the old messages you can link the source page to respect cc-by-sa.