Figurative language is a form of communication that includes word phrases not meant to be taken in their literal form, but rather evoke imagery or provide decorative use. Other types of phrases, called sound devices, are also a form of figurative language, and use repeating and similar sounds for additional emotional effect in written pieces.
A simile is a figurative phrase that compares two very different things using the words “like” or “as.” These phrases are usually used to emphasize an idea or fact, such as “selling like hot cakes” to indicate something is very popular and selling well, or “strong as an ox” referring to a person who is very strong.
In simple terms, a metaphor is like a concise, condensed simile. Similes are where two ideas are compared using the words “like” or “as,” such as “strong as an ox.” A metaphor removes the qualifiers -- the “like” or “as”-- and makes an implied comparison using familiar terms. “He is strong as an ox” simply becomes “He is an ox.”
Hyperbole -- pronounced “high-PER-bo-ly” -- is a figure of speech used to emphasize through overexaggeration. As with other figures of speech, it's used for effect and not meant to be taken literally. Examples include “loads of room,” “tons of money” and “waiting for ages.”
Alliteration is a sound device formed by the repetition of the same sound, usually a consonant, at the beginning of a word. “Dead as a doornail” and “footloose and fancy-free” are examples of alliteration. A subcategory of alliteration is tongue twisters, which involve words that contain the same sounds. “She sells sea shells by the seashore” and “Peter Piper picked a peck of picked peppers” are two well-known examples.
Assonance is a sound device that refers to word phrases with similar sounds repeated in the words, such as the “ee” sound in “easy to please.” These recurring sounds don't necessarily have to be vowels, as phrases such as “bright-eyed and bushy-tailed” are also assonance examples, due to the repetition of the "B," "T" and "D" sounds of the words.
The sound device onomatopoeia refers to words both derived from sounds and used to suggest sound. “Ping” and “tick, tock” are examples of words derived from sounds, while “R-r-r-i-i-i-p!” would be an example of a word visually imitating a sound.