The dialogue are inside BALLOONS. There are many different types depending on what the character is.

Sound effects and environmental sounds are presented without balloons, in bold or "3D" text in all upper case.

Also called the tails of speech balloons, these indicate which character is speaking the words in the balloon.  Thought balloons have Bubbles which lead to the character which they belong to.

Motion lines, also known as "speed lines" are lines that are used to represent motion; if a person or some other mobile object is moving such indicators of movement will follow in straight lines behind it.

Emotive Symbols are iconic representations used within comics and cartooning as representations of character feelings.

Narrator´s  words are inside the CAPTION.

PANEL is the basic unit of a comic book page, consisting of a single illustration. It is most often contained within a square or rectangular frame, although circular panels are not uncommon, and irregularly-shaped panels are also possible.