It's an awkward name: Isamay, pronounced Is-a-may. Isa is my paternal grandmother's name (shortened from Isabel) and May my maternal grandmother's (it comes, somehow, from Margaret). The amalgamation is, as you see, strictly alphabetical. Life, I feel, would have been much easier if they had chosen Maybel.
2010, Margaret Forster, Isa & May, Chatto & Windus, page 5