chrome: 71.0.3578.8 Dev

Steps to repro:
# With ChromeVox on and connected to a braille display, visit data:text/html,<input type="text">
# Type 'this is a test' into the edit box that appears
# Press routing keys at various points and listen to ChromeVox read the text that the cursor jumped over

Expected: ChromeVox only announces the letter under the cursor instead of entire jumped text
Or, an earcon is played before or after speaking jumped text to indicate the cursor position

Actual: Jumped text is spoken without any context for why it was spoken