Shompen appears to be related to the other Southern Nicobarese varieties, however Glottolog considers it a language isolate.

Parmanand Lal (1977:104)[2] reported the presence of several Shompen villages in the interior of Great Nicobar Island.

[7] However, Blench and Sidwell (2011) note that the 2003 book is at least partially plagiarized and that the authors show little sign of understanding the material, which is full of anomalies and inconsistencies.

For example, the word for "back (of the body)" is given as gikau, tamnōi, and hokōa in different sources; "to bathe" as pu(g)oihoɔp and hōhōm; and "head" as koi and fiāu.

In some of these cases, that may be a matter of borrowed versus native vocabulary, as koi appears to be Nicobarese, but it also suggests that Shompen is not a single language.

[8] However, Paul Sidwell (2017)[10] classifies Shompen as a Southern Nicobaric language, rather than a separate branch of Austroasiatic.