How can I force all the letters go left to right including the characters from right-to-left languages in all buffers? Currently it displays the lines with right-to-left characters bidirectionally.
Bidi reordering is controlled by the buffer-local variable
bidi-display-reordering. You make it default to false by adding the following incantation to your init file:
(setq-default bidi-display-reordering nil)