Nowadays, checking that a language has an English name in the upstream CLDR or in the local customization in the CLDR extension is defined as a step in the procedure to add a language to translatewiki. But in the past, it was not written in the procedure, so some languages still don't have a name there. This causes them to be displayed in their native name, which is often not written in the Latin alphabet. This happens, for example, on Special:MessageGroupStats, when showing the complete list of languages: the names of languages jje, kge-arab, kip, and several others are displayed in a non-Latin alphabet, and can't be read by people who don't know them.
All of these languages should at least have labels in English, which is the fallback for everything else.