When you hear someone say "little people", most people picture the leprechaun from Ireland. The ones in Finians Rainbow or Darby O'Gill and the little people. The ones who have the pot of gold at the end of the rainbow. Its just that many other cultures have their own version of little people.
For instance, the Hawaiians have the Menehune. They played a prevalent part in life over in the islands. Every time there was a thunder storm people would say that the Menehune were bowling. On the other hand, literature contains a ton of references of little people such as the brownies, dwarves, pixies, even fairies.
Many of these creatures have become popular since the release of the Hobbit and Lord of the Rings movies. Both the Hobbits and the Dwarves are much shorter than the normal people but they are not as short as some of the the little people found in legend.
In addition, many of the native American tribes have their own stories of little people. The Cherokee believe there are three types of little people. One group believes in revenge and getting even, the second are pranksters and the last group is helpful and likes to take care of people.
In Alaska, there are the Enukins, who live underground and are from the Point Hope/Kotzebue area. They often fill the boogeyman role in various stories. In the Norton Sound area, you'll find the Ishigaq who float above the ground and live like normal Eskimos but are only about a foot tall.
In Alaska, everyone seems to have a story of having run into the little people. If they have not seen one personally, a relative has seen one. In some places, you'll be told they ride snow machines, in others, boats. I don't think anyone has actually been able to snap a picture of a little person from folklore but in many places, people have an absolute belief in these folks. Its the same type of belief expressed by people when discussing big foot.