system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does google have a better spell checker than dedicated text editing programs?
gpt
Google's spellchecker watches what people do and learns from them.

The first time somebody made that particular mistake Google probably wouldn't have offered a very useful correction. However once enough people manually corrected their spelling it would've become the top suggestion.

Bing (another Microsoft product) automatically corrects comphreensive to comprehensive if you try and search it.

Maintaining this type of spell checker is quite complicated, you need a very large database of errors and corrections.

Microsoft's desktop software such as Office and Internet Explorer have a purely-offline spell checker. Compared to the online versions it's much simpler, the software has a dictionary of every word is knows, and some information on the most common errors (for example infornation automatically corrects to information). An algorithm decides which corrections to offer for a misspelled word, this algorithm is designed to work very fast on personal computer hardware; whereas Google and Bing's approach only really works thanks to their large computational resources.

Of course the closer you are to the actual word the better the offline algorithm will work. 'comphrensive' not only has the h in the wrong place but is also missing an e, Office offers comprehensive as the top correction for both 'comphreensive' and 'comprehnsive'.