> "2nd fruit in bear apple goat orange"[1], "7th digit in abc123def456ghi789"[2]
It barfs on these ones, but not like you predict (it's actually worse). "The 2nd colour in purple, belly, yellow, arm, white and blue"[3] gives back yellow, though, so it's not that stupid.
If you change yellow to silver, it gives you "colour silver," but if you look at the assumptions, it assumes silver is an element. Clearly it's not really getting the meaning of the sentence, and the fact that it's picking "yellow" is mostly coincidental, I think, as is also illustrated by your examples.
It barfs on these ones, but not like you predict (it's actually worse). "The 2nd colour in purple, belly, yellow, arm, white and blue"[3] gives back yellow, though, so it's not that stupid.
[1] http://www.wolframalpha.com/input/?i=The+2nd+fruit+in+bear+a...
[2] http://www.wolframalpha.com/input/?i=7th+digit+in+abc123def4...
[3] http://www.wolframalpha.com/input/?i=The+2nd+colour+in+purpl...