Ron Ackerman's suggestion that his family came from Germany may well be true, a change from Akerman to Ackerman, however does not necessarily support this. My home is in Chipping Norton, Oxfordshire, England and Ackermans have lived there from at least the 17th century - I have not researchd this, to be honest. I do know though that one generation is recorded as Ackerman, the next Akerman. Given the times literacy was not as important as today. An ancestor (19th c), for example, is buried in the nearby village of Adelstrop (which inspired the poem)and is William Akerman - his son is, again, Ackerman.
There is, by the way, an Ackerman Road in Chpping Norton.