Damn, its coming out around the same time Star Craft: Ghost. Choices...
For all technical purposes, if Nintendo was dropping Navi's/Tetra's Trackers because of translation problems (Pronouncing names and all), they could easily get help from proffesional Linguists (Dare I say cunning?....)
What they could do is refer to the International Phonetics Association (IPA), who could plausibly make so that Tetra could pronounce American Names. They could make a layering program of the most common sounds made in the English language so that the user inputs standard writing, the program turns that into to phonetic symbols, and the voice spits out the result.
Unfortunately, that would probably be more trouble than its worth, and would probably delay the game. Oh well, "2 out of 3 ain't bad..."
P.S Zelda finally giving birth to kids? Its about time!