The voice output for Appicenter's langues apps make use of Android's
Text To Speech (TTS) engine infrastructure.
Often TTS engines are pre-installed but they can also be installed from
the Google Playstore.
Engines can be selected and activated under menu [Settings] :: [Language&Input] :: [Text-to-speech output]
Typically voice sets for each desired output language need to be installed as well.
Older Android phones do not come with any TTS engine and newer android phones often lack a proper Portuguese voice set resulting in either no or very robotic sounding voice output. The default TTS engine installed on Samsung phones often causes problems and we recommend switching to the standard Google one instead.
The standard Google TTS engine is used on many phones and tablets and, in our experience, your best choice. It can be downloaded from the Play Store by following this link. Note that the engine behaves differently depending on whether the device is on-line or off-line. For off-line use you may need to download additional voice sets.
After installing the new engine do not forget to activate and configure it in the menu mentioned above.
If the standard Google TTS engine does not work for you several third party TTS engines are available in the Google Play Store to fill the gap. Below is commented list: