serious n00b.. NLTK in python 2.7 and 3.5

[metulburr]

Jordans-MBP:~ jordan$ sudo pip install -U nltk
Password:
The directory '/Users/jordanXXX/Library/Caches/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
The directory '/Users/jordanXXX/Library/Caches/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Requirement already up-to-date: nltk in /Library/Python/2.7/site-packages

pip is defaulted to python2.7 pip...you need to use python3.x pip
I am not sure how to do that on a mac though.