QGIS has a lot of documentation, partly translated. Please have a look into one of the documents below.
If you do not see working links to documentation above, it means that this documentation build did not copy the documentation sources into the website sources. You can also go to http://docs.qgis.org/2.0
We keep a copy of the documentation of QGIS 1.8 around here: http://docs.qgis.org/1.8
Although not translated we also build the documentation for the release QGIS which is currently developed. We call this version ‘QGIS testing’ and documentation can be found here: http://docs.qgis.org/testing