**Problem:**
Users can select `mul` as a language on the Special:NewItem page. If they fill out the description field and send the form, they will receive an error message, that says `mul` is not allowed for descriptions. We need to make this more intuitive.
**Notes:**
* The reason is that we only allow the language code `mul` for Labels and Aliases and not for descriptions (T313027).
* The UI language stays the preselected default.
* The list of available languages is sorted alphabetically (including "multiple languages").
**Mockup:**
| [[ https://www.figma.com/file/UMHGYSxln03lGx2z7GxzP2/MUL---Termbox?node-id=340%3A5829&t=CoqKoUFLGxpqjPdE-0 | Link to flow in Figma ]] |
**BDD:**
If an editor selects `mul` on Special:NewItem then we deactivate the description field.
GIVEN an editor has opened Special:NewItem
WHEN the editor selects the language code `mul`
THEN the description field is disabled
AND the description field is emptied
AND the explanatory text (see "Copy") is shown below the disabled field (inline message)
If the user selects any another language on Special:NewItem then w ego back to normal.
GIVEN an editor has opened Special:NewItem
AND the the language code `mul` is selected
WHEN the editor selects any other language code
THEN the description field is enabled
AND the explanatory text is hidden
**Copy:**
```
It is not possible to enter descriptions for multiple languages at once. Please provide a description after the Item is created.
```
**Acceptance criteria:**
[] If an editor selects `mul` on Special:NewItem then we deactivate the description field.
[] If the user selects any another language on Special:NewItem then w ego back to normal.
**Open questions:**
* Are there any other places where we need to consider this?