Mercury retrograde is moving backward instead of forward. In reality, that is just an illusion and only seems to move backward.
When Mercury is retrograde, it makes a person re-think, re-do, re-evaluate, etc.... Messages may be misunderstood; whispers may be overheard and mail or email may be misdirected.
Basically, it inspires one to re-do, review, re-read, repeat, re-think, all of which are conducive to learning and retention of knowledge. This is always a good time to finish unfinished project or take up refresher courses to better yourself. But, its not a good time to sign papers or important document because once mercury goes direct (forward) , the papers may not have been legally well-prepared due to mistakes in wording or typos etc...
But, remember that what i have stated will be felt more if a person has Mercury retrograde at birth. otherwise, the effect will be very minimal and Mercury retrograde cannot do harm if Mercury is well-placed in your natal chart and direct. And vice-versa.
