Though it is true that English is a phonetic language, where the symbols on the page represent sounds, the code is a bit more complex than that. English is in fact a morpho-phonemic language: a code that represents both sound and meaning.
One of the unique challenges of English is the fact that the spoken sounds often shift pronunciation when adding suffixes and prefixes. Consider the following two words:
These words are clearly related in meaning, however, the EA is pronounced as a long /ē/ in "clean" and a short
/ĕ/ in "cleanse." In order to retain the visual relationship in meaning, the person who decided how to spell these words chose to balance the relationship of both sound and meaning. The result is that EA must say at least two sounds.
This does not only happen with vowels. Compare the following words.
Notice that silent C in "muscle" actually is heard in the derivative "muscular."
The same is true with the GN phonogram.
Notice that the two-letter GN phonogram is used to spell "sign" because in some words the "g" sound is clearly articulated.
I believe it is the complexity of our code that has resulted in the widespread myth that English is illogical and full of exceptions. However, once we begin to understand how English really works, the language opens up in new ways and we can teach students critical thinking skills rather than relying solely on rote memorization.