**Context:**
Constraints System
**User story:**
As an editor, I want to define that all Items using a certain Property should have a Label in a specific language. This helps to ensure that all the mandatory Labels are added.
**Problem:**
We currently don't have a constraint that helps ensure certain Items always have a Label in a specific language. Currently, editors are solving this with a complex constraint: [[https://www.wikidata.org/wiki/Help:Property_constraints_portal/Label_language | Help:Property_constraints_portal/Label_language]]
**Example:**
* RKDartists ID ([[ https://www.wikidata.org/wiki/Property:P650 | P650 ]]) "Identifier for artists in the database of the Netherlands Institute of Art History". Items using this Property should have a Dutch label.
**BDD**
GIVEN a Constraint definition that requires a Label in language X for Property Y
WHEN an Item uses Property Y
AND does not have a Label in Language X
THEN a constraint violation is triggered for the statement using Property Y
**Notes:**
* We also want this constraint to work on Property pages. We probably want to ignore it on MediaInfo. We can't apply it on Lexemes, Forms, and Senses because they don't have Labels.
* If several languages are provided in the constraint then the constraint is satisfied if at least one of the languages has a label added.
* We are using "Wikimedia Language Code (P424)" as the qualifier.
* We are using a new item (“label in language constraint”) as the constraint type, not reusing the [complex constraint label language](https://www.wikidata.org/wiki/Q102746314) item.
**Acceptance criteria:**
[ ] constraint violations are triggered when an Item uses a Property with a Label language constraint but does not have a label in the specified language (see BDD)
**Open questions:**
*
**Community communication:**
Who we need to keep in the loop and in what way:
Who this could be interesting for and in what way:
**Original report:**
Label in language: An item using a certain property should at least have a label in this language or these languages. example defined on Property talk:P650 (https://www.wikidata.org/wiki/Property_talk:P650).
(part of https://www.wikidata.org/wiki/Help_talk:Property_constraints_portal#Improvements_for_2018 )
Currently implemented as "complex constraint", see [[https://www.wikidata.org/wiki/Help:Property_constraints_portal/Label_language | Help:Property_constraints_portal/Label_language]]