The biological process whose specific outcome is the progression of the soft palate from an initial condition to its mature state. This process begins with the formation of the structure and ends with the mature structure, whatever form that may be including its natural destruction. The soft palate is the posterior portion of the palate extending from the posterior edge of the hard palate. [ GOC:dph http://openisbn.com/search.php?q=0721662544&isbn=1/ ]