UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36

Steps to reproduce the problem:
https://jsfiddle.net/ThomasOrlita/mt87x2zc/

The minus sign is U+2212

var msg = new SpeechSynthesisUtterance();
msg.voiceURI = 'native';
msg.volume = 1; // 0 to 1
msg.lang = 'en-US';
msg.text = "let's try dash. value = -1. Let's try minus. Value = −1";
speechSynthesis.speak(msg);

What is the expected behavior?
It should say "minus one" in both cases.

What went wrong?
It says "minus one" and "one"

Did this work before? N/A 

Does this work in other browsers? No
 Not working as intended (Windows): Edge 42.17134.1.0, FF 61.0.2, Opera 54.0.2952.64, Chrome 68.0.3440.106, 70.0.3528.0

Working as intended: See comments at https://meta.stackoverflow.com/a/318126/4227998

Chrome version: 68.0.3440.106  Channel: canary
OS Version: 10.0
Flash Version: Shockwave Flash 30.0