There is, as yet, no reliable way to obtain acoustic measurements of 0 l 0 that alone regularly distinguishes between vocalized and unvocalized variants.
After each bout they perched on a branch and remained silent, vocalizing, or chasing intruders.
They were asked to repeat each stimulus word out loud, and only then to vocalize the target phoneme.
Then he shakes her arm (which is resting on his leg) and vocalizes quietly.
The two of them start to move and vocalize together excitedly, their arm movements and vocalizations mimicking each other.
When the child vocalizes after this long pause, there is no involvement from the adults.
Since the vocalization of 0 l 0 is difficult to determine impressionistically, a conservative approach was taken to identifying an 0 l 0 as vocalized.
Toddlers vocalize in ways that may or may not be meant for surrounding adult listeners.
