How to approach it ?
Language page contains the iso-639-3 code, upon which we name our Commons category.
So the creation of that property's value is a direct concatenation of Lingua Libre pronunciation-+ ISO-639-3.

Example :

• LinguaLibre Arabic : https://lingualibre.org/wiki/Q219
  • P-13 (ISO 639-3 code) : ara
• Commons Category LinguaLibre Arabic : https://commons.wikimedia.org/wiki/Category:Lingua_Libre_pronunciation-ara
• LinguaLibre Cantonese : https://lingualibre.org/wiki/Q221062
  • P-13 (ISO 639-3 code) : yue
• Commons Category LinguaLibre Cantonese : https://commons.wikimedia.org/wiki/Category:Lingua_Libre_pronunciation-yue

Could be done

• by hand ?
• by WikiJS script once allowed ?
• by modifying LL's language import script ? => it's a gadget

Gadget

• MediaWiki:Gadget-LinguaImporter
• MediaWiki:Gadget-LinguaImporter.js
• MediaWiki_talk:Gadget-LinguaImporter.js

Before to ask someone to code this...
IS THIS PROPERTY REALLY NEEDED SINCE ITS AN EXACT DERIVATIVE OF P-13 ?

I'am skeptical on the usefulness of this property and it's value (a concatenation of url root + iso639-3) within largely unknown language Q-items. Commons categories will be far more known. But I may miss the point, and other people may need it.

It may also be relevant, for languages, to add the url toward the .zip /datasets.

Dans T233917#6835684, @Yug a écrit :

Before to ask someone to code this...
IS THIS PROPERTY REALLY NEEDED SINCE ITS AN EXACT DERIVATIVE OF P-13 ?

Yes, no problem in principle because it is not the same datatype. P-13 is an external identifier while the new property could be either an external identifier or an URL. In case we choose external identifier (the best choice IMO), the URL formatter will be different. It is not a big deal to have two properties that have the same "identifier".

I've created P26 to link to Commons category relative to a language.
By the way, the code is not necessary the same as the ISO 639-3 code because some language/dialect does not have ISO 639-3 code (for example: Martinique Creole). Currently, all recordings for languages with no ISO code are in Category:Lingua_Libre_pronunciation-other. The problem about the category for language/dialect that do not have ISO code is described in T208641. So once we will have found the category name, we will be able to link to that category name with the new property.

So now, we need to add this new property to all already existing languages on Lingua Libre and to update the LinguaImporter gadget in order to take into account that property.

Thank for that info ! PS: is there a way to signal I read your comment without creating a comment myself ?

Yug, since you are a subscriber, it means you get a notification (by email for example), so no need to write a comment to say that you read the last message. So suscribe to all taks you are interested in or you can watch the full LinguaLibre project to be aware of all changes happening in any task.

I have updated the LinguaImporter gadget code in order to take into account the new property.