Letters are phonograms with strong clues about pronunciation. Numerals are pure ideograms with no clue about pronunciation. Modern English is a mix of phonogram

Letters are phonograms with strong clues about pronunciation. Numerals are pure ideograms with no clue about pronunciation. Modern English is a mix of phonograms and ideograms, with more of the former. Its very likely they trigger different subsystems of the brain. And in this case the ideogram subsystem was defective.