This is a misleading statistic. It refers not to reading ability, but to the number of people who have problems with standardised spelling. Spelling problems are not reading problems. The two abilities are not related.
Until the publication of Dr Johnson's dictionary in the 18th century, there was no adequate reference for people to check their spelling. People spelt as they thought the word sounded and, as English is only partly phonic, there were many variations. Queen Elizabeth I of England was extremely creative in her spelling of English words but, as the lady was also extremely competent in reading and writing in Latin and French, she could hardly be classed as illiterate.
Today, it is fashionable and convenient to follow a standard format for spelling although not all words have been standardised, such as "inquiry"
or "enquiry"? Or is it "jail" or "gaol"? Erratic spelling does not affect our ability to read.
The first principle in reading is the development of language. Without the acquirement of verbal thinking ability - sometimes called "inner speech" - reading cannot take place. The next step is learning to project our thoughts on to the written page where they meet the thoughts of the author of the writing. A two-way conversation takes place. It is this interaction that enables us to understand what we read.
Problems arise when the ability to interact is interrupted. Emotional disturbance is a prime factor in destroying this ability to communicate.
If, when young children come to school and they are emotionally disturbed, they will not learn to read. Or if children who are already at school become emotionally disturbed, their reading facility degrades. Parental break-up is a common cause of such problems.
Adults who are undergoing an emotional crisis will often have problems with understanding what they are reading. They read the words but, because they cannot concentrate on projecting their thoughts on to the page, they do not interact with the author. In such cases these people could be said to be dyslexic. But the condition is usually temporary. Solve the emotional problems and you solve the reading problems.
For the very few people with normal intelligence who apparently do not fit into this category, more research needs to be done. The statement that one in five children leave school unable to read adequately is wrong.
Tony Yarham Mouswald Dumfriesshire