What happens if you lie to a child during language acquisition?
You would need a conspiracy of many people to prank a child with this kind of thing, because kids are really good at tracking the information value of sources. If you give a different random word every time they'll discount you as an information source, if you give the same random word every time they'll learn it... and use it only with you (more or less, but increasingly so with age/experience.) See Birch et al. (2008) for more details.

You might also have fun with the literature on early bilingualism, which is basically this situation, right? Kids are phenomenal at this. See for example Liberman et al. (2017).


Birch, S. A., Vauthier, S. A., &amp; Bloom, P. (2008). [Three-and four-year-olds spontaneously use others’ past performance to guide their learning.][] Cognition, 107(3), 1018-1034.
Liberman, Z., Woodward, A. L., Keysar, B., &amp; Kinzler, K. D. (2017). Exposure to multiple languages enhances communication skills in infancy. Developmental science, 20(1), e12420.