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Waraikú (Araikú) is an extinct, poorly attested, and unclassified Arawakan language. The only record of this language is in a wordlist published in 1867 by Carl Friedrich Philipp von Martius. Both Kaufman (1994) and Aikhenvald (1999) leave it unclassified within Northern Arawakan.
Dixon, Robert M. W.; Aĭkhenvalʹd, A. I︠U︡, eds. (2006). The Amazonian languages. Cambridge language surveys (Digitally printed 1st pbk. version ed.). Cambridge ; New York: Cambridge University Press. ISBN978-0-521-57893-6.