ChuVNSongSong4.0 is new invented method of quick entry of Vietnamese characters that helps speed up typing by 40% with the help of a tool online named: chuvnsongsong.com - a free for typing Vietnamese sofware.
Or see full manual at: http://chuvietnhanh.sourceforge.net/CongThucChuVNSongSong4.0VaViDu.htm
Also, see manual article of the mehod of typing shortcut ChuVietNhanh (Tubinhtran) to Chu Quoc Ngu at link:
http://chuvietnhanh.sourceforge.net/GoNhanhChuVietCachTubinhtranVoiWinvnkey.htm...