On Jul 16, 1:13m, "Pete Dashwood"
There is no reason why spell-checkers can not cater for variants in
one dictionary. Word allows you to add your variant spelling without
invalidating the original dictionary spelling. One problem: wouldn't
you end up allowing all mis-spellings too? I don't know how modern
spell-checkers work (I last checked it out in 2003) but they are
inherently limited (2003) by their algorithm. The 2003 method involved
weighting each character position and multiplying by a nominal value
for the character, summing all products and then using the sum as an
index to a 4096 table of bits where 1 = valid spelling and 0 =
invalid. It was perfectly possible to calculate a sum for one mis-
spelled word which would point to a bit which indicated (incorrectly)
that the word was valid (even though other calculations could produce
the same displacement).
The book I read didn't tell me how Word checks for grammatical errors.