Information theory is a useful framework of research that has been recently adapted to be used in the field of cognitive workload study for pilot performance. Mental workload assessment and forecasting modelling outputs based on Shannon’s Law have showed up as relevant feedback for managers with responsibilities in designing and optimizing the learning procedures involved. Therefore, the aim of this article is to apply this methodology to propose a mental workload baseline, caused by listening practice in English as a foreign language for a dual educational system (Military-STEM) where students must achieve an Industrial Engineering degree simultaneously with Military Pilot studies distributed in a four-year term program. For such purpose, it is summarised a case of study where the Mental Workload Assessment-Information Theory (MWA-IT) and the NASA Task Load Index (NASA-TLX), as one of the most cited references on workload studies, have been used to propose a reference baseline of expected workload. The paper introduces first a review regarding English as a foreign language in academic background, the workload methodologies mentioned before and the case of study characterization that set the database used. Applying MINITAB software for statistical analysis it is concluded finally that the nondimensional workload reference baseline was, for MWA-IT within 36.5 to 92.6 meanwhile NASA-TLX was within 49.8 to 193.7, and also that almost 65% of the workload due English Listening proficiency achievement was caused along the first two courses, when advanced STEM subjects are taught and before the elementary pilot learning and practice program starts.