I guess it depends on which string(s) your talking about. There are a couple of places where changes can be made locally on your institutions site if you have admin privileges. See following locations
- Admin > Settings > User Interface Labels
- Admin > Menus
But the vast majority of translations are handled in
Weblate and are packaged with AtoM. My colleague here in The National Library of Wales has done most, if not all, of the Welsh translations in Weblate so far, but anyone can contribute. These changes are universal though and I guess contributors from different institutions may want to discuss strings they feel should have been translated differently. I believe we've translated strings as close as possible to the primary English strings. If it's making changes to the main language file from Weblate within your local instance I'm not sure how you would go about that or if it's at all possible. I'm sure Artefactual will be able to give guidance on that.
Hope this helps and please let me know if we can help any further.