How is the name of the Willamette River pronounced?: Information Roundup
Few American place names are more persistently misspelled and mispronounced than that of the Oregon river that flows into the Columbia several miles below Portland. It is correctly spelled Willamette and pronounced will-LAHM-et; it is commonly misspelled Williamette and mispronounced WILL-yum-ett, as if the word consisted of the given name William and the diminutive suffix ette and meant "little William." The river was named after a tribe of Indians found living in that region by the early European explorers. It is supposed to be derived from the same root as Walla Walla and Wallula and to signify "running." No evidence supports the popular theory that the word literally means "long stream" or "large and beautiful stream." The spelling varied widely in early writings. Walamet is regarded as the closest approach to the aboriginal word. We find it spelled Ouallamat and Ouallamet by the first Canadian hunters, traders, trappers and forest rovers, who later substituted i for a in the first syllable and added the ette termination. In Astoria (1836) Washington Irving spelled the name Wollamut and explained that it was pronounced with the second syllable accented; in The Adventures of Captain Bonneville (1837) he spelled it Wallamut, apparently a deliberate change. In 1874 the Oregon legislature fixed Willamette as the official spelling in state laws and records.