Google has incorporated a massive dictionary into their functionality. After years of watching users, they were able to take that dictionary and create an automatic spelling correction feature called "Did You Mean."
The "Did you mean" feature showed up in November 2008, and it has a profound impact on SEO. Let's investigate why...
Whenever Google recognizes what it decides may be a misspelling, it will not return search results for that misspelling, instead it will correct the spelling and display a message saying "Showing results for {corrected spelling}. Search instead for {incorrect spelling}." This is a failsafe in case you really were searching for something with that incorrect (read: unpopular) spelling.
Prior to this automatic spelling correction, it was important to include misspellings on your website just in case someone had an accidental search. It was also important to register domain names with misspelled words. But now we don't worry about it... much.
Here's a specific example.
If you sell Gelin Abaci rings, you should have a designer line webpage dedicated to the line. The Title should be "Gelin Abaci Tension Jewelry, Wedding Rings." That title should correctly show even when people misspell Gelin Abaci.
Here are some search examples:
Search for "gellin abbachi" and you see this: "Showing results for gellin abachi. Search instead for gellin abbachi"
Search for "gellin abachi" and you see this: "Showing results for gelin abaci. Search instead for gellin abachi"
Prior to 2008, if you wanted to help people who didn't know how to spell correctly, you would need to include those misspellings in the descriptions of your page. That process always made the websites look sloppy, and unprofessional. Thankfully, you don't have to do that anymore.
On the other hand, if you sell a designer line with an Italian, Spanish, French (or any other potentially difficult language) name you do need to worry about the misspellings.
A customer doing a search for Belle Etoile may have more difficulty with the Google search. With this example you may want to consider having a page dedicated to the designer using the title "Belle Etoile Jewelry, Silver Jewelry, Fashion Jewelry." But you might also want to have another page on your website with the title "Latest European Jewelry Fashion Trends" and on that page use the name Belle Etoile along with other descriptions of the jewelry.
That second page about European jewelry will act more like a traffic magnet than the dedicated Belle Etoile page because it will appear more as an educational page than a sales page.
The bottom line today is that you don't need to worry about misspellings anymore. The next time your SEO professional mentions misspellings as the only way to ensure your site is found, you will safely know that they are a few years behind on their training.