A word element attached to a root word that changes its meaning is called an affix . New words are created from the root word (a base), by adding an affix before or after it. When a word element is attatched <em>before </em> the root, it is called a prefix (Example: in, un : infidel, unhappy). If it is placed <em>after</em> the root, it is called a suffix (Example: less : careless).
He was using his body language and gesticulation to make a digresion and push the speach in a new direction for a brief amount of time. Digresion is commonly used in public speaking when one is giving and example, introducing new topic, bringin a guest in, and so on.