of course you should write in english ... you can't expect everyone in here to learn your language .... Lots of people don't speak english as a first language in here ... as long as you try your best to express yourself in english, you will do fine ...
$.63 is very good for most niches, although it's common to find random clicks that will be higher. If you could average $.63 per click for a large number of clicks you'd be doing better than about 99% of Adsense users.
$0.63 is more then most people receive for one click. Earnings do fluctuate but i expect that price will be lower in time.
I have received a click almost the same value as what you got. It depends, it could be high on some niches while it could be just the average on other niches.
most likely it is random, so just concentrate on building up traffic. Answer is traffic will be the kind for adsense :_)
You guys resurrected this post way back 2007, I get $0.50 sometimes. Assuming you get $0.63 * 100 in a day that's $63 $63 * 30 in a month that's $1890. That's okay for an in house job.