Answer:
Two idioms or figures of speech that English language learners might find confusing are "it's raining cats and dogs" and "barking up the wrong tree."
"It's raining cats and dogs" is an idiom that means it's raining very heavily. English language learners who are unfamiliar with this expression might take it literally and become confused as to how it's possible for cats and dogs to fall from the sky.
"Barking up the wrong tree" is a figure of speech that means to pursue a mistaken or misguided course of action. English language learners might have difficulty understanding the literal meaning of this phrase and might struggle to make the connection between barking and pursuing a wrong course of action.