Apron, adder, and other words that used to begin with 'n'... | OxfordWords blog - http://blog.oxforddictionaries.com/2014...
"Because it is impossible in fast speech to tell whether the sound /n/ belongs to the indefinite article or the following noun, over the years the letter N has on rare occasions migrated from one word to the other. This process is referred to as metanalysis." - Maitani
"Below are a few examples of words that had their beginnings in beginning with N." - Maitani