Explore the propagation of fermions on curved backgrounds in the context of the Ishibashi-Kawai-Kitazawa-Tsuchiya (IKKT) matrix model in this 23-minute conference talk. Delve into the coupling of spin to background geometry using the Jeffreys-Wentzel-Kramers-Brillouin (JWKB) approximation. Discover how the results align with Einstein-Cartan theory expectations despite the absence of local Lorentz invariance in the IKKT framework. Learn about the additional coupling to the totally antisymmetric part of the torsion that distinguishes these findings from general relativity. Briefly examine the case of Friedmann-Lemaître-Robertson-Walker cosmic background solutions as a special application. This talk, presented at the Workshop on "Large-N Matrix Models and Emergent Geometry" at the Erwin Schrödinger International Institute for Mathematics and Physics, is based on research published in Physical Review D by E. Battista and H. Steinacker.