Would half six in the predominant language of your country make more sense to mean 5:30 or 6:30
The correct way to mention it’s 6:30 in English would be ‘it’s half past six’ However some people from the UK use the expression ‘half six’ from time to time.
Note: in some languages such as Spanish and French half six would not make much sense but even then it would make more sense to be 6:30 than 5:30