? Using the entire ? (3770) ? DD event sample collected by the CLEO-c detector, the ? decays D0 ? ?? e+ ?e , D0 ? K ? e+ ?e , D+ ? ?0 e+ ?e and D+ ? K 0 e+ ?e are studied via a tagged analysis technique that reconstructs semileptonic decays opposite fully reconstructed hadronic decays. Partial rates are measured in several q2 bins, and these are combined with form factor parameterizations to extract branching fractions and form factor parameters. Taking form factor predictions from lattice QCD, the CKM matrix elements |Vcd | and |Vcs | are also calculated.