def predict_letters(letters, lts_lambda, silences=True):
    """
    To predict using Letter To Sound Rules we pad the word with zeros (as done
    in Festival LTS training. Then we choose the right tree for each character
    in our word and predict the phonemes, that are returned in a list.)
    """
    phonemes = []
    word_list = [0, 0, '#'] + letters + ["#", 0, 0]
    for word_index in range(3, len(word_list)-3):
        word_char = word_list[word_index]
        tree_lambda = lts_lambda[word_char]
        phone = tree_lambda(word_list, word_index)
        phonemes.append(phone)
    if silences:
        return phonemes
    else:
        return [x for x in phonemes if x != "_epsilon_"]