It's tempting to think of Gui as the Spanish form of Guy, but it's short for Guillermo.

With a sound that brings to mind at once "whim," "vim," and "win," this is one Dutch boys' name with serious potential for use in the English-speaking world.

Common in Holland, the appealing Willem (as in de Kooning and Dafoe) makes William fresh and distinctive.

A common surname that was popular as a given name in the late 19th and early 20th century, Willis dropped off the US Top 1000 back in the early 90s, just as alternative William diminutive, Liam, began to skyrocket.

Wylie is one Celtic surname with as much appeal for girls as for boys. Wylie is ripe for spelling variations: Wiley is as appropriate as Wylie but when you spell it Wylei, as Corey Parker did for his son, you're getting into yooneek naming territory.

A Saudi Arabian royal name that has remained within its own culture.

This form of Liam ranks in Puerto Rico's Top 100, and is also popular with French-speaking parents in Europe and Canada.

Cooler than Ernest and less Muppet-like than Ernie, the Finnish Erno may be the best way to honor someone with an Ern- name.

A great choice for a native Swedish speaker, but not as user-friendly as some of the other international short forms of William — Pim (Dutch), Gwil (Welsh), and of course, Liam (Irish).

Sometimes heard in Scotland, where its heyday was in the times of Robert Burns and Sir Walter Scott, here we would prefer the Germanic version, Wilhelmina, brought into the spotlight by the conniving character on "Ugly Betty."

The cute short form gained prominence when it was used for young Prince William of England.

Intriguing short form of Guilherme, heard in Portugal and Brazil. Guion Bluford was the first African American to go to space.

The Wylie spelling (with that feminine Y) is much more common among girls than Wiley, but both have been climbing the ranks. Could Wiley be the next Riley?

Maori form of William

Alternate form of Ville, also seen as a surname.

If you want to go waaaaay beyond William, consider this Welsh form, which can also be spelled Gwilym, Gwilim, or Gwillym.

Scottish surname-turned-nickname from William or its female equivalents. Wilkie has ranked for girls just a handful of times since US baby name records began.

Yavuz Selim was a 16th-century sultan of the Ottoman Empire, which grew dramatically over his eight-year reign. Boys in Turkey are given this double-barreled first name in his honor.