Gray Emutail
or Madagascan grassbird or feather-tailed warbler (Chích cỏ Madagasca, Bradypterus seebohmi)
The bird is found only in Madagascar. 

The grey emutail (Bradypterus seebohmi), also known as the Madagascan grassbird or feather-tailed warbler, is an emutail in the family Locustellidae.

Locustellidae, Locustella is from Latin and is a diminutive of locusta, "grasshopper".
Bradypterus: Greek bradus slow, sluggish; -pteros -winged (pteron wing).