1. Put <!--more-->in your post test and it will create the break and the desired link. I propose to not let that be done by a plugin as it is also the task of a blog author to write good appetizers.
2. Language depends on the Theme but you can as always edit the theme. Most offen you will find something in Design -> Editor -> Main Index Template (index.php) -> the_content('Blablah read on')
Do you think it could be the fault of the web host? Or may be the problem is rooted deeper?
I think it is always truncated before a < (not necessarily the first) and it has to do something with the german Umlauts äöü. Truncation is than more likely.