from my developmental psychology textbook...

Yet another route to the formation of the first word is taken by Samoans, who believe that once children begin to walk, they become cheeky and willful. In accordance with this belief, the only word that Samoan parents acknowledge as a child's first word is "tae," which is a Samoan curse word meaning "shit." They explain this remarkable singularity of initial speech as confirmation of Samoan common knowledge - that young children are defiant and angry. In fact, young Samoan children may make a number of sounds that might be interpreted as words, but Samoan adults choose to hear and acknowledge only "tae."