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