Decomposition of a $\text{N}=2$ extended scalar superfield into irreducible supersymmetry representations

$\text{N}=2$ extended supersymmetry in four dimensions is considered from the point of view of the two simple supersymmetries contained in it. The $\text{N}=2$ scalar superfield of general form is decomposed into irreducible SU(2)-extended superfields. The three new superfields with SU(2) internal symmetry obtained in this manner are completely described.