3) Readers learn a lot about characters from how they speak and what they say.  This is 'dialogue'.  One person speaking alone is a 'monologue'.
When a person has an accent or certain speech habits, that's 'dialect'.  Dialect should be used sparingly, only enough to show the reader that's how the character sounds.

Choose a place your character is from.  Now decide how that character feels about going to a new school. 

You are walking up the steps of the school, and there is a teacher standing with a parent and 2 students at the doorway.

Tell your story.