Don’t just look at the Sun sign though because a water Sun has a high chance of having an Air Mercury which would make them a lot more communicative. A water Sun with a water Mercury however would be secretive.
Don’t ask me why Libra- an inanimate object- is classed as voiced. I assume it’s because Libra is sometimes represented as justice herself, blindfolded and holding the scales- therefore Libra can speak.
Edit- Some have commented thinking that mute signs are mutable signs. They’re not. Mutable is a modality along with cardinal and fixed. There’s one mutable sign for each element. Mute signs are a traditional concept based on the idea that the animals that symbolise the water signs are the only animals in the zodiac who are unable to vocalise sound and they use non-verbal communication as a result. This reflects on the water signs who are inclined to do the same.