I'm unsure which language choose as fallback. I'm thinking on french due to the colonial past of Algeria, where I think most people still understand/use the language and Shawiya being in Latin script. Arabic is out of the question for me as this is a latin script language. I'd appreciate some guidance here @Amire80 - thanks.
I've also seen https://en.wikipedia.org/wiki/Kabyle_language as candidate, but I'm not sure here.
Hi again @Amire80: @Raymond and myself are not sure which is the "official" name for Shawiya. ISO639-3 names it "Tachawit", Wikipedia mentions 2 other similar names so we doubt which one to choose. Also, insisting on my question above at T194047#4187192, I am not sure which fallback language, if any, should we use. I propose French, but I'm not sure either. Thanks for your help.
SIL states at https://iso639-3.sil.org/code/shy that the language name is Tachawit. I don't think we should be deviating from the standards unless the language name recorded at SIL is wrong, in which case SIL must be corrected first. "Community said so" is a rather weak reason. Rather they should state why the language name recorded at SIL is wrong, and maybe someone submit a change request at SIL. If SIL accepts the change, we could rename it on core afterwards.
SIL only records the names of languages in English (compare the page you linked to… well, any other language code). This is the autonym, and I think the native speakers know best what their own language is called.