[Hawthorn]

>> English is actually almost two separate languages: one is the English that is spoken, and the other is the English that we write <<

Entirely true. And your observation is a useful one.

But on the other hand, I doubt that we can find another modern language (except maybe Esperanto) where -- to one degree or another -- the situation is basically different.

That is, while spoken and written always are somehow related, they are never so closely related that a high degree of competency in reading automatically ensures competency in conversation.

[gleeaikin]

Over 50 years ago I took one semester of spoken French (total immersion) and three semesters of written Italian (also known as the grammar translation method). Today I can communicate about the same when speaking with native speakers.