Use the Transifex formatting for the pt-BR translation.

android/res/values-pt-rBR/strings.xml

-<?xml version="1.0" encoding="utf-8"?>
-<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
-  <!--
-        Source: App icon label.
-        Description: The name of the application.
-    -->
+<?xml version='1.0' encoding='UTF-8'?>
+<resources>
+  <!--Source: App icon label.
+        Description: The name of the application.-->
   <string name="app_name" translatable="false">eSpeak</string>
-  <!--
-        Source: Activity title.
-        Description: Title for the Settings activity.
-    -->
+  <!--Source: Activity title.
+        Description: Title for the Settings activity.-->
   <string name="tts_settings_label">Ajustes de TTS do eSpeak</string>
-  <!--
-        Source: Preference title.
-        Description: Title for the preference that controls default voice pitch.
-    -->
+  <!--Source: Preference title.
+        Description: Title for the preference that controls default voice pitch.-->
   <string name="setting_default_pitch">Tom</string>
-  <!--
-        Source: Preference title.
-        Description: Title for the preference that controls default speech rate.
-    -->
+  <!--Source: Preference title.
+        Description: Title for the preference that controls default speech rate.-->
   <string name="setting_default_rate">Velocidade</string>
-  <!--
-        Source: Dialog text.
-        Description: Status message shown when installing voice data.
-    -->
+  <!--Source: Dialog text.
+        Description: Status message shown when installing voice data.-->
   <string name="installing_voice_data">Instalando dados de voz…</string>
-  <!--
-        Source: Dialog message.
-        Description: Alert dialog prompting the user to set eSpeak as their default TTS engine.
-    -->
+  <!--Source: Dialog message.
+        Description: Alert dialog prompting the user to set eSpeak as their default TTS engine.-->
   <string name="set_default_message">O eSpeak não está configurado como o mecanismo padrão de texto para fala.</string>
-  <!--
-        Source: Dialog message.
-        Description: Alert dialog telling the user that voice data installation failed.
-    -->
+  <!--Source: Dialog message.
+        Description: Alert dialog telling the user that voice data installation failed.-->
   <string name="voice_data_failed_message">O eSpeak fracassou ao instalar os dados de voz. Por favor verifique o cartão SD.</string>
-  <!--
-        Source: Dialog message.
-        Description: Alert dialog telling the user that an unknown error has occurred.
-    -->
+  <!--Source: Dialog message.
+        Description: Alert dialog telling the user that an unknown error has occurred.-->
   <string name="error_message">Desculpe, o eSpeak fracassou em iniciar.</string>
-  <!--
-        Source: Label text.
-        Description: Label informing the user of the current text-to-speech language.
-    -->
+  <!--Source: Label text.
+        Description: Label informing the user of the current text-to-speech language.-->
   <string name="current_tts_locale">Voz padrão</string>
-  <!--
-        Source: Label text.
-        Description: Label informing the user of how many voices are installed.
-    -->
+  <!--Source: Label text.
+        Description: Label informing the user of how many voices are installed.-->
   <string name="available_voices">Vozes instaladas</string>
-  <!--
-        Source: Button label.
-        Description: Button for launching general text-to-speech settings.
-    -->
+  <!--Source: Button label.
+        Description: Button for launching general text-to-speech settings.-->
   <string name="tts_settings">Ajustes gerais de TTS</string>
-  <!--
-        Source: Button label.
-        Description: Button for launching eSpeak-specific settings.
-    -->
+  <!--Source: Button label.
+        Description: Button for launching eSpeak-specific settings.-->
   <string name="engine_settings">Ajustes de TTS do eSpeak</string>
-  <!--
-        Source: Label text.
-        Description: Label informing the user that eSpeak is loading resources.
-    -->
+  <!--Source: Label text.
+        Description: Label informing the user that eSpeak is loading resources.-->
   <string name="loading">Carregando, por favor aguarde…</string>
-  <!--
-        Source: Spoken aloud.
-        Description: Sample text spoken aloud when the user is trying out a language.
-    -->
-  <string name="sample_text">Esta é uma amostra de texto falado em <xliff:g>%s</xliff:g></string>
-  <!--
-        Source: Variant preference labels.
-        Description: Labels for possible voice variant/gender/age values.
-    -->
+  <!--Source: Spoken aloud.
+        Description: Sample text spoken aloud when the user is trying out a language.-->
+  <string name="sample_text"></string>
+  <!--Source: Variant preference labels.
+        Description: Labels for possible voice variant/gender/age values.-->
   <string-array name="default_variant_entries">
     <item>Masculino</item>
     <item>Masculino (Variante 1)</item>
     <item>Idoso (Masculino)</item>
     <item>Idoso (Feminino)</item>
   </string-array>
-  <!--
-        Source: Rate preference labels.
-        Description: Labels for possible rate multiplier values.
-    -->
+  <!--Source: Rate preference labels.
+        Description: Labels for possible rate multiplier values.-->
   <string name="status">Status</string>
   <string name="tts_version">Versão de eSpeak</string>
   <string name="speak">Speak</string>