When the movement of a sign is articulated smaller than is specified in its underlying phonological form, this is called movement reduction, and when the sign is articulated larger, this is called movement extension. Whispering and shouting in sign languages often involve these kinds of movement modifications. A distinction is made between movement modification that still involves the same joint(s) as phonologically specified (PHONOLOGY 3.1.3.1.), and modification as a consequence of joint shift (PHONOLOGY 3.1.3.2.).