Correlation of Intensity and Magnitude
A common feature of animal communication systems is the correlation between the intensity
and length of the signal and the magnitude of the message.
The greater the distance a food source is found from the hive, the more prolonged is the waggle portion of the bee dance.
Aggression displays by animals (which do communicate the message and so are candidates to be considered as a language) are graduated.
Consider dogs which first bare the teeth, then growl, then bark and finally charge.
Many animals try to make themselves look larger.
For example, cats raise their backs and fluff their hair
Because these displays are direct analogues to the message, they are easily interpreted.
Is this a common property of human language?
Not of language, but of its production.
Shouting versus calm and quiet production of the same sentence indicated different emotional states of the speaker.
Note that humans have similar communication systems:
Smiling, frowning, pouting, etc., are graduated and indicate the emotional state of the individual.