Lesson
The better writing systems such as Polish, Italian and Spanish are over 90% predictable. If you know how to pronounce a word, you know how to spell it.
English is about 40% phonemic and 40% predictable. There are patterns and regularities in English. If you know the regularities then you have about an 85% chance of spelling a word correctly.
The Second Edition Webster's spelt millennium - millenium.
A recent report on US freshman showed over 25% couldn’t spell Professor.