"Gribble" Natural Recordings by Native Speakers
Gribble is a noun that can refer to the sound of talking or murmuring, especially in a low, indistinct, or muffled way. For example, "The children's gribble could be heard from outside the classroom." It can also refer to the sound of insects or small animals making noise.
Greyish refers to a color that is closer to grey than to either black or white. It can also mean a thing that is dull or lackluster, rather than being bright or vibrant. For example, "The greyish tone of the paint didn't add much warmth to the room."