Ainu and Great Andamanese are relatives (proved by Prefixation Ability Index and Verbal Grammar Correlation Index)
Prefixation Ability Index (PAI) allows us to see whether languages can potentially be related (languages can potentially be related if their PAI values don’t differ more than fourfold); Verbal Grammar Correlation Index (VGCI) completely answers the question whether languages are related (testing of VGCI on the material of undoubtedly assembled stocks shows that VGCI values of distant relatives should be about 0.4 and more while VGCI of unrelated languages show values of VGCI about 0.3 and less). Having applied these methods to Ainu language I got the following: PAI has shown that Southern but not Northern direction is perspective for searching for Ainu language potential relative. VGCI of Ainu and Austronesian stock is 0.26; VGCI of Ainu and Mon-Khmer stock is 0.24; it means that Ainu is completely unrelated with both. From the other hand VGCI of Ainu and Great Andamanese is 0.38 that is evident proof of their relatedness. Also in the case of Ainu and Andmanese data of linguistics correlate well with those of genetics since both populations have D as main Y DNA. It seems that Ainu and Andamanese are relics of Negrito racial group that was spread rather wide in Southern and Southeast Asia; remains of this population also can be seen in Malaysia, in Thailand and in Philippines. Also I suppose that languages potentially related to Ainu-Andamanese stock probably can be found among so called West Papuan languages.
Key words: Ainu; Andamanese; PAI; VGCI; typology; comparative linguistics