@Override
		public Language getLanguage(LanguageID languageID) throws LanguageNotFoundException {
			try {
				return langService.getLanguage(languageID);
			}
			catch (LanguageNotFoundException e) {
				LanguageDescription langDescr = oldLangFactory.getLatestOldLanguage(languageID);
				if (langDescr != null) {
					return oldLangFactory.getOldLanguage(languageID, langDescr.getVersion());
				}
				throw e;
			}
		}
Language service which includes all languages, including old and deprecated
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/debug/GenerateOldLanguagePlugin.java