According to google translate, apparenty she keeps moving around her toungue and screaming which eventually cause her to exhaust all of her energy (which as an abused koyu she has very little of). She's literally too tired to live.
Amid the despair caused by her now unmoving feet and the suffering brought forth by her hunger, Maricha directed the last of what that remained of the nutritions in her core to verbally assault her mother, and died.