Mirror writing – is formed by writing in the direction that is the reverse of the natural way for a given language, such that the result is the mirror image of normal writing: it appears normal when it is reflected in a mirror. It is sometimes used as an extremely primitive form of cipher. A common modern usage of mirror writing can be found on the front of  ambulances, where the word  AMBULANCE” is often written in very large mirrored text, so that drivers see the word the right way around in their rear-view mirror.

Some people are able to produce handwritten mirrored text. Notably, Leonardo da Vinci wrote most of his personal notes in this way. Mirror writing calligraphy was popular in the Ottoman Empire, where it often carried mystical associations.

In children – mirror or reverse writing is found in some children.

It’s known as Dyslexia or reading disorder, is characterized by trouble with reading despite normal intelligence. Different people are affected to varying degrees.  Problems may include difficulties in spelling words, reading quickly, writing words, “sounding out” words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. When someone who previously could read loses their ability, it is known as alexia.  The difficulties are involuntary and people with this disorder have a normal desire to learn

Reasons

Dyslexia is believed to be caused by both genetic and environmental factors but There is no exact method for finding the true origin of mirror writing in children . In some cases it’s found as a result of accidental brain damage or neurological diseases, such as an essential tremor, Parkinson’s disease, or spino-cerebellar degeneration.

Courtesy- https://en.m.wikipedia.org/wiki/Mirror_writing