We use the localisation feature for most of our forms, as we tend to design them for our local users (e.g. South American, African, etc) and also for our HQ users (English). 

When we apply in form validation, the validation message can only be in one language, thus only really works for one group of users. It is complicated given that the message is conditional, so perhaps it is better if the conditions are separated from the values. E.g. condition = {weight >= 1} value = "Weight is too low".  The value could be localised so in Spanish it would read "Peso demasiado bajo" when the same condition is met and the user's locale is ES.

The values could be added to the list of localisation fields in the "Localization" section.