Thank you for the security update suggestion. I just updated a few days ago. I checked again for updates just now. My Mac says it is up-to-date and I can't upgrade to a newer OS. It wasn't the newest model available at the time. I preferred the ports offered on this model of MacBook over the newer version and so now need to decide when to bite the bullet and get a new Mac. Love this Mac and it hasn't given me a lick of trouble....unlike the replace-every-two years HP laptops (and awful Windows) I've had in the past.
The spellcheck on Safari was the culprit. Don't know what turned it back on recently, because I always set preferences to suggest--not change spelling. But, thanks to you on this forum, the problem is resolved.
Thank you. Diana