This is used to filter the list of languages returned. However, the
filtering is not needed on the engine side as the client can simply
enumerate through all the available voices instead.

The android.speech.tts.engine.CHECK_TTS_DATA intent should just
check that the TTS data is OK. It should not attempt a
download/install of the TTS data.

Portuguese (Brazil) is only used in Brazil, whereas Portuguese
(Portugal) is used in other Portuguese-speaking countries. Therefore,
it is standard practice to have a pt and pt-BR translation. I don't
know why the eyes-free port of eSpeak decided to do things
differently.

The idea here is that whenever the user changes one of the parameter
values via the SeekBar control, it is reflected immediately by eSpeak.
This is similar to how e.g. the brightness preference UI works.
However, instead of updating every time the value changes while the
slider is being moved, it is updated once the touch interaction is
finished.

Also, if the user Cancels or exits the dialog with the back button,
the old setting value is restored.

The ADT lint warnings flagged the value text as "consider making
the text selectable", however if you do TalkBack will cause the
first character to be read every time the seekbar changes poisiton
(due to the text being updated via the setText method).

This is annoying and confusing, so textIsSelectable is set to false
to supress the lint warning.