Why An Year?

There is a particularly strange fossilized English error that many native Portuguese speakers commit, the explanation of which depends on your perspective of the world. For simplicity's sake we'll call these two view points - nature and nurture. The error in question is the disproportionate number of times the article an is used before the word year.
The 'nurturites' believe this is a direct function (fault) of the over generalized rule:
y sometimes acts as a i (therefore, if this is true, logically, an must be used before words that start with y). The blame for this vulgarity is squarely placed on the shoulders of some under- qualified English teachers in their Native country. This explanation at first glance seems quite simple and straightforward, however, upon further scrutiny, some inconsistencies begin to appear when we test this hypotheses against other words that begin with y such as: yacht, yellow and yarn. Although some students continue to misuse an with words such as the ones above, the incidence is noticeably lower as compared to the number of times an year is said.
So what is it with the word year that seems to trigger the usage of the inappropriate article an instead of the correct a?
The "naturites" say they have the answer. To them it's a simple matter of transposing. The word for year in Portuguese is ano (the first two letters are phonetically equivalent to English), clearly it follows that people will think of the word ano when they want to say the English equivalent year. So, if you belong to this school of thought, when prefacing the word year the Native Portuguese speaker will instinctively choose an over a. Again, this reaction is more muted when prefacing other y-first words like: yard, yogurt, or Yankee.
Both arguments have merit and like any good argument create new questions to ponder such as: if this is true for Native Portuguese speakers could it also be valid for Native Spanish speakers?