Tena Quichua (ISO 639-3: quw) belongs to the Quechuan language family, as part of the peripheral variety Quechua IIB (Torero 1964, Cerrón-Palomino 1987, Gordon 2005). It is spoken in the Eastern Amazonian region of Ecuador on the Napo River above the mouth of the Rio Coca, primarily on three tributaries: the Misahualli, the Arajuno, and the Ansuc. Tena Quichua is bounded on the North and East by Napo Quichua and on the South by Pastaza Quichua. Previous research on the division of Ecuadorian dialects is summarized by Carpenter (1984: 3–4). Although it is beyond the scope of this Illustration, we hope that our description of Tena Quichua will prove useful in future work on the relations between these three Amazonian dialects of Ecuadorian Quichua. Below, a brief summary of Tena dialect identification and formation is given, followed by a description of present-day bilingualism in the region and data collection procedures.