It is common to find surnames similar to Functioning. This is because many times the surname Functioning has undergone mutations.
The fact that there was no unified spelling for the surname Functioning when the first surnames were formed allows us to find many surnames similar to Functioning.
Errors in writing, voluntary changes by the bearers, modifications for language reasons... There are many reasons why the surname Functioning may have undergone changes or modifications, and from those modifications, surnames similar to Functioning may have appeared, as we can see.
Discerning whether the surname Functioning or any of the surnames similar to Functioning came first is not always easy. There are many reasons that could have led to the surname Functioning being written or pronounced differently, giving rise to a new, different surname Functioning with a common root.