When you work with globalization, you define in every template which fields will vary depending upon the language by setting whether the property for that field should be "locked" for globalization or "open". This is done by using the unique value per language setting.
Properties that are set as a unique value per language are editable in all languages enabled on the website. This is normally the case, for example, in the property forming the HTML Editor, so that editors can enter content for the pages in the different languages. Properties that are not set as a unique value per language can only be edited in the language in which the page was created (the original page language). These fields will be grayed out in Edit mode with an icon indicating which language is the original language.
Imagine that the property defining the sort order field is not set as being a unique value per language, i.e. the Unique value per language check box is not selected. When you create a new page, you will be able to set the sort order in the original page language, but when you create a version of the page in another language, the sort order field will not be editable. This results in the sort order being the same for all the languages on the website. If you want the sort order to be different for each language, select the Unique value per language check box.
When a property is changed from being a unique value per language to not being a unique value, all the existing values for that property will be deleted. This means that if the property for the Editor is changed to not have a unique language, all the text that has been entered in the Editor for all the languages on the website will be permanently deleted.
Set a property to be editable per language