Is it normal that i spell words and count the letters in my head?

Say, for example, you walk up to me and say
"Hello, how are you today?"
In my head, I would spell each word, but I would also group them in numbers.
This is what would be in my head if I grouped the letters by 4.
"Hell ohow arey outo days?" (I would add the "s" on the end to make that group equal 4).
This seems so bizarre to me and I'm just wondering if anyone knows what this means.