**Disclaimer:** I am not  sure what kind of "explanation" you are looking for. I would guess that you are after the  observation (due to Hitchin),  that complex Lagrangian submanifolds become special Lagrangian after rotating the complex structure.

**Observation:**
Let $X$ be a hyperkaehler manifold. Let $\{I,J,K\}$ be a triple of complex structures,
satisfying the quaternionic identities, and let $\{\omega_I,\omega_J,\omega_K\}$ be the respective Kaehler forms. Let $M\subset (X,I,\omega_I)$ be a complex-lagrangian submanifold
for the complex-symplectic form $\omega_J+i\omega_K$. Then $M$ is a special lagrangian submanifod of $ (X,J, \omega_J,\Omega = (\omega_K+i\omega_I)^{\dim M})$.

(Actually, if $\dim M$ is odd you must either take $i\Omega$ as your holomorphic volume form, or relax the definition of special lagrangian. ) 
So given a real-analytic Kaehler manifold, you embed it as the zero-section of the cotangent bundle, take the Kaledin-Feix metric on a (formal) tubular neighbourhood, and rotate the complex structure.