deordinalize fails on non-numbers

[droundy]

Just glancing at the code, deordinalizing "last" would give "la". Similarly, "first" would give "fir", while I would have expected it to give "1".

To me this definitely qualifies as a bug. Not sure what the correct behavior is, but at a minimum this should be documented. Ideally it wouldn't affect words that are not actually ordinals.