Spelling isn't easy! Especially English which isn't phonetic.
Here is a ready to go test for B1 and up students of some of the most difficult words in English to spell.
Students fold their sheet and listen and spell the words. Then unfold and check their spelling.
A template is provided so you can use your own words to quiz!
Also check the answers and meaning with this handy presentation. Don't ask students to spell words they don't know the meaning of!