Voice cracks, voice breaks, you name it.
In: Biology
To add onto the other answers, coordination plays a role as well as changes in physiology. The range of sounds required in human speech is pretty large and it takes a serious amount of coordination to make your anatomy do the right things at the right times to make the correct sounds.
The sound begins in your vocal folds, travels up your throat, and goes out your mouth and nose. So your vocal tract is basically a tube with a bend near the open end. There’s a physical phenomenon in acoustics which is demonstrated in [this video (demo at 1:20)](https://youtu.be/F64xcPKKES8) that also applies to your vocal tract; basically, a property of tubes is that certain pitches can’t resonate through them as well as other pitches. So as these people try to vary the pitch of their voice with the tube against their mouth, you can hear what is essentially a simplified voice crack (or a yodel). The pitch at which the yodel happens depends on the length and diameter of the tube.
Obviously your head and neck are way more complicated than a solid tube, so the pitch at which your voice cracks happen aren’t fixed. The position of your anatomy affects where the cracks happen. As you go through puberty, you gain practice avoiding these positions (because it’s really embarrassing, and people tend to hate feeling embarassed) and thus avoiding the cracks.
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