You can log in to your smartphone by talking to it. Current security systems don't protect enough against imitators. The best way to ensure voice authentication is secure is to start with the sound.
For bilingual children, the constant switching between languages is like a frequent exercise for the ears and the brain.
Here's what one man from around 3,300BC actually sounded like.
What effect does music have on the developing brains of babies who haven't even learnt to talk?