This study considers a set of terms, fet, gol, and éigem, for vocalizations that are associated with the figure known as Bríg or Brigit in several medieval Irish texts: Cath Maige Tuired, the prose dindshenchas on Loch Oirbsen, and Lebor Gabála Érenn. The terms occur in etiological myths for the invention of caíned 'keening' in Cath Maige Tuired and the prose dindshenchas; the instance in Lebor Gabála Érenn is ambiguous. There has been some question as to whether these texts present fet, defined by DIL as 'a whistling or hissing sound', as part of ritual lamentation, or have included it for another reason. The three terms also occur in Cath Findchorad, as names for a trio of demonic sisters who prophesy death and destruction before a battle. This article attempts to determine the meaning of fet in in these sources, and the relationship among the texts.