The human faculty of language (FL) is legible to the faculty of performance (FP=articulatory-perceptual (AP)/sensorimotor systems+conceptual-intentional (CI) systems). How good a solution is FL to the legibility conditions that are imposed by FP (the Legibility Problem)? The Linear Correspondence Axiom (LCA) is a legibility condition imposed at the FL-AP interface (PF). The principle of Full Interpretation (FI) is a legibility condition imposed at the FL-CI interface (LF). I propose that FL's solution to the LCA and to the FI is optimal in the sense that it respects the Economy conditions, e.g., the minimization of derivational steps, the lack of superfluous steps, and the last resort nature of operations. At the descriptive level, I show that English, Hindi, and Japanese exhibit the identical computational procedure with respect to wh-movement. The multiple-wh effect in Japanese can be handled by the Extended (Cyclicity) Condition alone, which is a realization of negentropy within the human FL. Given the Overt Wh-Category Movement Hypothesis, the argument/adjunct-wh asymmetry with respect to island effects is accounted for in a simpler and more natural way. The standard government-based ECP account is dispensed with.