The Names and Families of Clan Maclean
(cont'd)
This whole scenario was made more complex during the main periods of Scottish emigration as these generally involved those with the lowest levels of education and who were often unable to read or write. When these people arrived in places like America, Canada, Australia, New Zealand, and South Africa and were recorded as immigrants, those taking the details often had major problems understanding the accents involved and thus simply reverted to recording names phonically and thus surnames evolved yet again.
So, although a person may now spell their name McLean or McClean or Maclaine (or whatever) their ancestors may have spelled the family name in a variety of ways and the most distant ancestor almost certainly spelled it MacGillieoin.