That's brilliant that you are starting to be able to project your voice!
Wow, you are starting to be able to make louder sounds now with your voice! Fantastic!
ご質問ありがとうございます。
① "That's brilliant that you are starting to be able to project your voice."＝「声が大きく出るようになり始めているとは凄いね！」
② "Wow, you are starting to be able to make louder sounds now with your voice!"＝「わー、大きな声が出せるようになってきたね！」
"Fantastic!"＝「素晴らしい！」
ご参考に。
アメリカ合衆国 
