Languages are needed to read certain books. * If the student has a difference of 50% between his % of knowledge and the teachers, the student will gain between 7% to 12%. * between 40 to 50% = gain between 6% to 10%. * between 30 and 40 = gain between 5% to 8% * between 20 and 30 = gain between 4% to 6% * between 10 and 20 = gain between 2% to 5% * between 10 and 0 = gain between 1% to 3% * less then 0 = gain between 1% to 3% If you are not an IG Lord or Lady then divide every gain by two.