What respiration in frogs do humans not use?

frogs use their skin for their respiration (since it is filled with capillaries). For most amphibians, 90% of their respiration is done through their skin. Frogs can also breath through the lining in their mouth which also contains capillaries, so a large amount of gas exchange can take place there. Frogs are able to breath through a pair of lungs as well, though this is used as more of a back up.