[Xapian-discuss] Spelling correction confusion

[Francis Irving]

If I spell "commission" wrongly with an s instead of a t, Xapian (via
the QueryParser's get_corrected_query_string function) is finding
the right spelling:

http://www.whatdotheyknow.com/search/commistion

However, if I miss the s out completely, it doesn't find it:

http://www.whatdotheyknow.com/search/commision

Any idea why that is?

Missing the last i out also doesn't work:
    http://www.whatdotheyknow.com/search/commisson
But if I miss the last o out, it finds the right spelling:
    http://www.whatdotheyknow.com/search/commissin

Reading the algorithm here, I can't see why this would be...
    http://xapian.org/docs/spelling.html

Any suggestions? Even just ideas for debugging it would be great.

Thanks for your help,

Francis