Intuition has made me suspect that G. could be factoring spellchecks on sites for some time, toward indicating overall site quality. Not to mention discouraging the visitors themselves.
Could anyone recommend a tried and true utility that could be run locally as I want to avoid some of the junk on other sites? Or not be limited to less than 100 pages.
Could you explain what you mean. What does "factoring spellchecks on sites " mean? Also, you asked for a “tried and true utility”. A utility to do what, exactly?
I would agree that Google is probably using some type of spell check to help judge the quality of your site. This factor alone will probably not make or break your site quality score, they most likely look at numerous signals to determine site quality.
I personally try to make sure all spelling is correct on my sites so they do not send any low quality signals. Even if they do not use this signal, users who come to your site will most likely not think highly of your site if there are lots of spelling mistakes.
Being US based would Google use a US English spellchecker? My site is aimed at the UK and uses UK English, would Google consider it incorrect? There are also variances to English in other countries which are perfectly acceptable within that country but might not be elsewhere. I can’t really see how Google could allow for all the possibilities.