In 4:11-12 these pronouns are plural and refer to James' audience. (See: [[rc://en/ta/man/translate/figs-you]])
## but are a judge of it ##
This could be translated as "but you are acting like the person who gives the law."
## Only one is the lawgiver and judge, God, the one ##
"God is the only one who gives laws and judges people, because he is the only one"
## Who are you who judge your neighbor? ##
This is a rhetorical question James uses to scold his audience. It could be translated as a statement: "You are just a human and cannot judge another human." (See: [[rc://en/ta/man/translate/figs-rquestion]])