Amanuensis is a noun that refers to an assistant who takes dictation. 

Our word of the day comes from a Latin phrase that refers to ‘a servant at handwriting.’ More recently, an amanuensis is likely to be thought of as a secretary or assistant. Here’s an example of the word in use:

After years of being an amanuensis, I was eager to make a career change. All that dictation can get tedious after a while.