Most of the standard works tend to be weak on regional variations, it is possible that at some time all the above may have been valid, i.e.: local to a particular region, but may have not survived. Without a doubt the main area from where the surviving family members appear to have originated is Devon, England. The earliest references I have found in Devon are Un Verdas de la FOLE, Smith Tarton Hundred 1243. Andrew FOEL, Tynmouth 1316, invitation to a Popes Coronation. Dr Guppy in 1890 suggests FOALE is a South Hams surname.
The name is also found in the Maramures North Western Romania Region and in Timis, Caras-Severin & Arad (historically called Banat) in Western Romania. In modern Romanian the name means 'bellows' so possibly ancestors made or operated bellows for the metal working industry, there is also a regional meaning of the word defining the belly/stomach area. There is a river in Romania, a tributary of the Dragan River, named Paraul lui Foale. A number of Romanian 'FOALE' families emigrated to the USA at the turn of the 19th century and their ancestors are there today.
Since 1900 there have been two forms of pronunciation for the name in current use, the most common FOAL ('as in baby horse' - which from my own experience and several others who have contacted me is the only way to make the name understood on the telephone) and FOE-LEA. (as in toe and sea or foe-are-lea). The most common spelling being FOALE, with a few spelt FOALLE or FOAL.