Retired in ISO 639-3: Split into Fanamaket [bjp], Niwer Mil [hrc], and Warwar Feni [hrw]
Excerpt from change request document:
The Tangga language is said to be spoken in three different locations; the Tangga Islands, the Feni Islands, and mainland New Ireland, PNG. A 2005 survey conducted by SIL-PNG showed that the three varieties spoken in the three locations consider themselves distinct, though sharing a common history. Even though all three groups say there was a time when they all spoke the same language, now they no longer understand each other. (Please note the accompanying survey report is a draft.)
This is shown through a lexicostatistic comparison, where Fanamaket scores an average of 69 with Warwar Feni, highest is a 70, and an average of 69 with Niwer Mil, highest a 69 (see pages 16 and 17 of the accompanying survey report).
This is verified by the reported comprehension between the varieties. Speakers of Warwar Feni and Niwer Mil said that children understand very little or nothing of the Fanamaket variety, while speakers of Fanamaket said the same of the other two varieties. (19 and 20).
The lexicostatistic comparison between Warwar Feni and Niwer Mil showed an average score of 83, the highest being 84 (pages 16-17).
The reported comprehension between the varieties is stark. Respondents in two Niwer Mil villages reported that children can understand nothing of Warwar Feni, while respondents in the other two Niwer Mil villages reported that children can understand little of Warwar Feni. On the other side, respondents in three Warwar Feni villages reported that children can understand nothing of Niwer Mil while the other two villages reported children can understand only a little. (pages 19 and 20)
When asked specifically about the acceptance of language development in the other varieties, each said they would refuse to use them. Each group wants language development in their own variety. (page 22)
"People from the Tanga Islands, Feni Islands, and the three New Ireland villages perceive themselves to be speaking different languages. They recognise that the three languages are related and they report that they have a shared origin on New Ireland, but speakers of any one dialect do not think that the other two dialects sound good, they do not think that the other two dialects are very comprehensible, and they generally say they would not be willing to use literature in either of the other two dialects. People from each group would prefer to use literature in their own dialect. Even if Warwar Feni speakers could understand literature in the Niwer Mil dialect, they probably would not use Niwer Mil materials. Therefore, Niwer Mil and Warwar Feni speakers should not be grouped together to use the same literature.
In conclusion, for the purposes of language development, Niwer Mil, Warwar Feni, and Fanamaket can be considered different languages and should each have their own literature." (page 23)