A question about conlangs and Navajo

Merhaba!

http://home.bluemarble.net/~langmin/navajo.htm made me think of my polyconlang,
Laan /la:n/, and I decided I could use Navajo's idea of having few nouns but
using phrases instead. How many roots will I need? I can't seem to find a
(good) online Navajo dictionary.

Thanks,
--Trebor