For recording in languages that do not have any ISO 639-3 code, categorisation has to be improved. Currently it can be "Category:Lingua Libre pronunciation-pas applicable" (https://commons.wikimedia.org/wiki/File:LL-Q942602-Davidgrosclaude-capleugi%C3%A8r.wav) or Category:Lingua Libre pronunciation-other (https://commons.wikimedia.org/wiki/File:LL-Q36759-Assassas77-%E5%8D%B5.wav).
For these languages, an idea would be to use category like "Category:Lingua Libre pronunciation-XXX" where XXX is the name of the language in English.
In addition, Lingua Libre should check if several languages that do not ISO 639-3 code have the same name, the category should include the name of the country (it is stored in the Wikidata item of the language). Thus, it would be "Category:Lingua Libre pronunciation-XXX (YYY)" with XXX the language name in English and YYY the name of the country in English.