1. Prepare your system:
sudo apt-get install build-essential xorg-dev gcc xlibs-dev libxft-dev

2. Install Unicode fonts
sudo apt-get install msttcorefonts

3. Download and extract new version of xvnkb at http://xvnkb.sourceforce.net
cd xvnkb/
./autogen.sh
./configure ; may be -> check it ./configure --use-extstroke,

4. Edit config.h file contain these line:

#define __VK_CONFIG_H
#define VK_CHECK_SPELLING
#define VK_USE_EXTSTROKE
#define VK_NEED_UCHAR
And complile : sudo make && make install