Parents commonly ask me, “Isn’t dyslexia seeing words backwards?” The simple answer is no, it is not seeing words backwards.
Dyslexia affects sequencing, or putting information in order. Spelling is a sequential activity – the letters of a word must be in the right order to be spelled correctly. Someone who is dyslexic may have a good idea of which letters are in a word, but he/she is not sure of the correct order.
For example, I gave the Word Identification and Spelling Test (WIST) to an 8-year-old boy before beginning tutoring. The spelling word was “shop.” The little boy sounded out the word in a whisper voice and wrote S-O-P. He knew it didn’t look right, so he tacked on an H at the beginning. 
The same little boy spelled “they” H-T-E-Y. He knew all the right letters, just wasn’t sure of their sequence. The right kind of tutoring can help students like him put sounds and letters in their proper order.