Board Thread:Naruto Discussions/@comment-26508646-20150704031517/@comment-734582-20150711221242

LegionZero wrote: He could speak to Son because of Kuramas innate ability as a Tailed Beast to do so. Not because Kurama had his Chakra. Checking the chapter, it seems they gave Naruto their chakra so that he could pull them out of the Juubi later.