I was asked on Twitter today about the difference between enquire/ enquiry and inquire/ inquiry.
Strictly speaking, inquire and enquire are interchangeable and the grammar police won’t be able to arrest you for using either of them.
Interestingly, however, we seem to be moving towards a differentiation in meaning. It’s now becoming normal to use enquire to mean to ask, for instance “Can I enquire about the price of the room?”
However, inquire is used to mean “investigate” (the i at the start of the word is a good way to remember the rule).
So a policeman investigating a bank raid might turn up on your doorstep and inquire where you got the money for that new helicopter on your driveway.
In the same way, a court would hold an inquiry rather than an enquiry as it’s more formal.
I hope that answers your enquiry, Twitter!