class WordTransformer {

    public static String getPastParticiple(String verb) {

        if (verb.isEmpty()) {
            return verb;
        }

        String stemmedWord = stemEnglishWord(verb);
        EnglishVerb englishVerb = IRREGULAR_VERBS.get(stemmedWord);

        if (englishVerb != null) {
            return englishVerb.getPastParticiple();
        }

        return getRegularVerbPast(stemmedWord);
    }

}