By voice we mean that people produce sounds for speech. People can be recognised by their voice. People also sing with their voices. So we hear a sound or tones that are produced by the voice.
If you want to speak or sing well, you have to train your voice. You learn to speak clearly and to speak for a long time without your voice starting to hurt. If you speak for too long, you can become hoarse. This also happens when you have an inflammation, for example when you have a cold.
You can tell from your voice whether someone is happy, sad or angry, for example. Singers use their voices to make music. Singers' voices are differentiated according to their pitch: a low male voice is the bass, followed upwards by the baritone and the tenor. Then, for women, comes the alto voice and finally, at the top, the soprano.
However, the expression "voice" is also understood to mean something else. "Casting one's vote" is an expression often used in politics. It means that those entitled to vote can make their opinion known in a binding way. For example, they can say "yes" or "no" to the construction of a new tunnel or a school. In a democracy, the majority wins. However, the opinion is usually not expressed, but written on a pre-printed piece of paper and thrown into an urn. Nevertheless, one also speaks of the vote in this context.