Look at some common questions on [nltk-users](https://groups.google.com/forum/#!forum/nltk-users) (e.g. [this](https://groups.google.com/forum/#!searchin/nltk-users/unicode/nltk-users/G2SruQz91fg/rZ0lT6RXwZ8J)), and [nltk issues](https://github.com/nltk/nltk/issues) (e.g. [this](https://github.com/nltk/nltk/issues/915#issuecomment-78037032)), and address them in the Unicode discussion.