UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.67 Safari/537.36

Steps to reproduce the problem:
Preconditions:
form exists:
<form>
  Username: <input type="text" name="username" required>
  <input type="submit">
</form>

1. Run screen reader NVDA or JAWS
2. Navigate to the 'submit' button by 'Tab' key
3. Press 'enter' key on the 'submit' button

What is the expected behavior?
- reader narrate: "alert please fill out this field."

What went wrong?
- reader doesn't narrate the alert message 

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 70.0.3538.67  Channel: stable
OS Version: 10.0
Flash Version: 

when I tested it with 
- NDA or JAWS + Firefox reader was narrating alert message.
- Edge + Narrator, the same reader was narrating alert message.

From the testing above I assume it is issue related to the Chrome.
 

Deleted: required-not-narrated.mp4 265 KB

	required-not-narrated.mp4 265 KB View Download