You can call it a voice print. Microbehaviours are how to describe aspects of voice that are too small to individually explain or consciously train. When we think about glottal behaviour, which is just a fancy way of saying the intricate ways we make sound go brr, it contains things as big as vocal weight and as small as onsets. So what’s smaller and harder to affect than something as tiny as onsets? Well, microbehaviours.
When you take a feminine voice, lower the pitch, make it heavier in vocal weight and drop the resonance a bit, you expect to hear a typical masculine sound. So, why is it then that sometimes we hear voices just like this that are feminine? Why is it that we also sometimes hear voices just like this that are masculine, even though they have the same basic characteristics. The answer is - probably - microbehaviours.
Microbehaviours are an aspect of voice that is near impossible to train consciously. Usually we just practice for so long that we get really used to that configuration and learn new microbehaviours and develop more consistent glottal behaviour over time. That’s the problem though: it takes a long time - in the order of years.
There are ways to train it however and the main one is by finding a voice that displays the characteristics you want and mimicking it intuitively.
Here’s an audio introduction to the concept.