Browsing Brazilian Portuguese translation

Translators: Orca has an "echo" setting which allows the user to configure
what is spoken in response to a key press. Given a user who typed "Hello
world.":
- key echo: "H e l l o space w o r l d period"
- word echo: "Hello" spoken when the space is pressed; "world" spoken when
the period is pressed.
- sentence echo: "Hello world" spoken when the period is pressed.
A user can choose to have no echo, one type of echo, or multiple types of
echo. The following string refers to a command that allows the user to quickly
choose which type of echo is being used.