Hi,
yes of course probably you were a bit to quick during the installation procedure for the smartphone but it's no problem to get the English language file on your smartphone: Simply copy the file SiDiaryEn.txt from the PC (home folder of SiDiary, default is c:\program files\SINOVO\SiDiary\) to the Smartfolder where you have installed SiDiary.
After restarting SiDiary on your mobile device you should see English in the language (Sprache) selection box on the Settings tab (Einstellungen).
Let me now, if this can fix the issue?