'OK with these aren't you?' looks at tag questions.
For a language that 'carries agreements' right through a sentence in far less detail than many others (at least in Europe), English has quite a funny little habit in how it forms Tag Questions:
'He's not going to do that again, is he?'
(The 'he' agreement carried right from front to back of the question, and the repeat turned from negative to affirmative)
How reliable are you at forming such questions accurately? You can't just hide behind an all-purpose 'tag' as in some other languages (German: 'nicht wahr?'; French: 'n'est-ce pas?', etc.) ... can you?