English doesn't have consistent rule-based writing spelling, so kids have to essentially memorize all word spellings. Since some kids suck at this game, there have to be compensation strategy to fill in the blanks. At some point it went too far and the last resort compensation strategy became the main method children are taugh (tough? tof? damn this language, it makes no sense) to read.
To be fair, English is much more consistent in the letters->sounds direction than it is in the sounds->letters direction. While being able to say a word in English hardly indicates a spelling due to there being several ways to represent the same sound, the opposite direction works pretty well, since there isn't a ton of ambiguity about what sound a given letter/digraph makes. The "exceptions" to that rule tend to be cases where we weaken (shorten/shwa/skip) unstressed vowels.
