Alternative to ibus typing booster Ubuntu 18.04

ibus-typing-booster is available in the official repositories since Ubuntu 20.04. Unfortunately, it is not available as .deb package for releases of Debian or Ubuntu prior to 20.04.

That means you will need to compile it yourself. Here are some brief instructions (source):

sudo apt-get install ibus libibus-1.0-dev
git clone git://github.com/mike-fabian/ibus-typing-booster.git
cd ibus-typing-booster
./autogen.sh
./configure --prefix=/usr --libexecdir=/usr/lib/ibus
make
sudo make install

The official manual is available here.