Current spell-checking systems (at least the ones that I’m familiar with) highlight the whole word upon finding a typo in it:
Typo highlight in MS Word
The system does know that I only misspelled one single letter. But instead of giving me the hint on just that it makes me read the complete word and then read the suggested word and act upon it:
Words makes me find out where exactly a typo occurred
I though it’d be great to show exactly where a typo occurred whenever possible:
A 'lightweight' solution for highlighting exactly where a typo is by making the underline bold
A straightforward way of highlighting the typo
It’d also be great to see what letter in the variant suggested by the spell-checking software gets corrected in case of misspelling:
Having the corrected letter highlighted would also be nice
