input-method-exit-on-first-char

input-method-exit-on-first-char is a variable defined in `mule-cmds.el'.
Its value is

nil

Documentation:
This flag controls when an input method returns.
Usually, the input method does not return while there's a possibility
that it may find a different translation if a user types another key.
But, if this flag is non-nil, the input method returns as soon as the
current key sequence gets long enough to have some valid translation.