Sum in J is +/ not, $&$%^%$%M. Is +/ really too hard to comprehend? I agree with you that APL is historically important, but J is Ken Iverson's last and greatest gift to the programming community. He used the 26 years between the release of APL and J to address many of the shortcomings of APL. Take a look at http://bit.ly/hMmGWV for some background.