@Override
		public LanguageDescription getLanguageDescription(LanguageID languageID, int version)
				throws LanguageNotFoundException {
			Language language = oldLangFactory.getOldLanguage(languageID, version);
			if (language != null) {
				return language.getLanguageDescription();
			}
			LanguageDescription languageDescription =
				langService.getLanguageDescription(languageID);
			if (languageDescription.getVersion() != version) {
				throw new LanguageNotFoundException(languageID, "version: " + version);
			}
			return languageDescription;
		}
Language service which includes all languages, including old and deprecated
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/debug/GenerateOldLanguagePlugin.java