In every video where a deaf person tries hearing aids/cochlear implants for the first time, they understand spoken language. How? /u/Snowytequila No such thing as stupid questions

How are they able to understand what the words mean if they never heard them? I understand if sign language is used alongside words but its not always the case.

How are they able to understand what the words mean if they never heard them? I understand if sign language is used alongside words but its not always the case.