My dad had an MRI on his back and I do not understand what the doctor found?

Posterior disc herniation L2-3 with left foraminal narrowing. Posterior disc herniation with mild inferior migration L3-4 effacing the thecal sac with moderate left lateral recess and foraminal narrowing. Posterior disc hernation L4-5 with inferior migration of disc material in the left lateral recess effacing the thecal sac narrowing the left lateral recess. Accompanying facet hypertrophy is contributing to bilaterial formaminal stenosis and nerve root impingement. Mild levoscoliosis and straightening of the normal lumbar curvature.