In the present invention a bit line decoder circuit a method of selecting bit lines for read and program operations is described for a twin MONOS memory cell array. A block of twin MONOS memory cells is partitioned into sub-blocks wherein decode signals select bit lines to be read and programmed, and select adjacent bit lines to provide bias for the read and program operations. The bit lines are partitioned into even and odd addresses within each sub-block, and an even and odd address sub-block selector connects the selected bit line along with adjacent bit lines to sense amplifiers and memory chip I/O.