protected function isFirstWordOfSentence($index)
    {
        if ($index == 0) {
            return true;
        }

        $twoCharactersBack = mb_substr($this->title, $index - 2, 1, $this->encoding);

        if ($this->isPunctuation($twoCharactersBack)) {
            return true;
        }

        return false;
    }