I think this is the gist of the whole thread here. On one hand it's an exercise in pedantry, on the other trying to be scientifically/mathematically precise using language which can often be ambiguous. :rolleyes:
Once again the answer is tied to the concept that acceleration is a vector concept possessing both magnitude AND direction. So even if the magnitude is constant, if the direction changes, as it does in circular or elliptical motion the acceleration always changes (provided that no other forces...