Intonation helps you understand the deeper meaning behind the words you hear.
You'll understand exactly what people mean when they stress different words or change their tone of voice. You'll be able to decipher key information that isn't said in words, but with a change in inflection.
Intonation helps sound more like a native speaker and improves your accent.
Your pitch will sound more natural, and less robotic. Your voice will sound more expressive and less monotone. Your accent will improve because you'll be using the music and melody of English correctly.
Intonation helps you communicate how you feel without needing the perfect words.
You'll understand how to use your voice more powerfully to emphasize key parts of your message. You'll be able to sound more polite, more professional, and more respectful of other people's ideas.
Intonation helps people follow what you're saying and encourages better conversations.
You'll know how to keep people listening by breaking your ideas into smaller pieces and helping them follow along.
You'll feel confident reflecting other people's emotions back to them with your voice.
You'll be able to use the rise and fall of your pitch to encourage people to respond to your questions, to wait before jumping in, or to invite them to keep talking.