[sp332]

A binary search on a sorted list can only work if you know whether the item you're looking for is earlier or later in the sequence. Not knowing the order of the alphabet is like not knowing the order of the numbers 0-9. You have to fall back to a linear search, which is prohibitively slow for many day-to-day operations.

[petercooper]

Appreciate the point in the first sentence; that's just what I was looking for :-) But..

Not knowing the order of the alphabet is like not knowing the order of the numbers 0-9.

This is where I'm unsure. In relation to literacy, is not knowing the order of the alphabet as severe as not knowing the order of digits in numeracy?

It's hard to imagine not knowing the order of the alphabet, but I don't think it would impede most of my day to day speaking and reading, whereas not remembering the order of 0-9 would basically render my numeracy skills useless since digits are inherently ordinal whereas the order of the alphabet could be entirely different and still work (if we all agreed on the new order).

[sp332]

Nope, that comment was purely in the context of sorting. I doubt it would have much impact on literacy.