In previous papers we introduced and studied a 'relativistic' hypergeometric function R(a + , a − , c; v,v) that satisfies four hyperbolic difference equations of AskeyWilson type. Specializing the family of couplings c ∈ C 4 to suitable two-dimensional subfamilies, we obtain doubling identities that may be viewed as generalized quadratic transformations. Specifically, they give rise to a quadratic transformation for 2 F 1 in the 'nonrelativistic' limit, and they yield quadratic transformations for the AskeyWilson polynomials when the variables v orv are suitably discretized. For the general coupling case, we also study the bearing of several previous results on the AskeyWilson polynomials.