There is no need to read the file every time when user input something.
vocab should be always up to date with the file. More over - you read the file once at the start of check_input and then read the file yet again if input is list.
If you can't explain it to a six year old, you don't understand it yourself, Albert Einstein
How to Ask Questions The Smart Way: link and another link
Create MCV example
Debug small programs
How to Ask Questions The Smart Way: link and another link
Create MCV example
Debug small programs