...that's the question. When I was thinking about founding my own blog, I didn't actually mean to use English at all. Then I decided to use English only and translate to Czech and Welsh using Google Translate, but in the end my final decision is writing it all in both English and Czech and use Google Translate only for Welsh version (unfortunatelly I can say only 4 sentences in Welsh myself).
First of all I want to practice more practical and technical English. That's why I will create everything in English at first. Then I plan to use Google Translate to help me convert it all to Czech. So in the end there should be two equal versions of the web in different languages.
Practicing English is not the only reason why I have decided to create multilanguage website. My girlfriend is Welsh, so it is important for me to make her understand everything here. She (and also her sister) is also the reason why I support Welsh version here using Google Translate on-line service.