diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index a695728..c2cea6e 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -55,6 +55,9 @@
         <activity
             android:name=".content.task.NumberActivity"
             android:screenOrientation="fullSensor" />
+        <activity
+            android:name=".content.task.SelectLetterActivity"
+            android:screenOrientation="fullSensor" />
         <activity
             android:name=".content.task.StarActivity"
             android:screenOrientation="fullSensor" />
diff --git a/app/src/main/ic_launcher_authentication_2-web.png b/app/src/main/ic_launcher_authentication_2-web.png
deleted file mode 100644
index e559a16..0000000
Binary files a/app/src/main/ic_launcher_authentication_2-web.png and /dev/null differ
diff --git a/app/src/main/ic_launcher_student_image_collection-web.png b/app/src/main/ic_launcher_student_image_collection-web.png
deleted file mode 100644
index d858733..0000000
Binary files a/app/src/main/ic_launcher_student_image_collection-web.png and /dev/null differ
diff --git a/app/src/main/java/org/literacyapp/authentication/helper/AuthenticationHelper.java b/app/src/main/java/org/literacyapp/authentication/helper/AuthenticationHelper.java
index ebfff91..c9ad377 100644
--- a/app/src/main/java/org/literacyapp/authentication/helper/AuthenticationHelper.java
+++ b/app/src/main/java/org/literacyapp/authentication/helper/AuthenticationHelper.java
@@ -22,10 +22,13 @@
  */
 
 public class AuthenticationHelper {
+
     private static final double[] countSteps = { 0, 5, 10, 15, 20, 25, 30, 35, 40, 45 };
     private static final double[] exponentialDelayStepsInMinutes = { 30, 60, 120, 240, 480, 960, 1920, 3840, 7680, 15360 };
 
-    public static synchronized void updateCurrentStudent(Student student, Context context, boolean isFallback){
+    public static synchronized void updateCurrentStudent(Student student, Context context, boolean isFallback) {
+        Log.i(context.getClass().getName(), "updateCurrentStudent");
+
         LiteracyApplication literacyApplication = (LiteracyApplication) context;
         DaoSession daoSession = literacyApplication.getDaoSession();
         AuthenticationEventDao authenticationEventDao = daoSession.getAuthenticationEventDao();
@@ -46,6 +49,8 @@ public static synchronized void updateCurrentStudent(Student student, Context co
     }
 
     private static void addExponentialDelayIfSameStudent(Context context, AuthenticationEventDao authenticationEventDao, Student newStudent){
+        Log.i(context.getClass().getName(), "addExponentialDelayIfSameStudent");
+
         List<AuthenticationEvent> authenticationEvents = authenticationEventDao.queryBuilder().orderDesc(AuthenticationEventDao.Properties.Time).list();
         if (authenticationEvents.size() > 0){
             int countOfRecurrentLogins = 0;
diff --git a/app/src/main/java/org/literacyapp/content/task/LetterGraphemeActivity.java b/app/src/main/java/org/literacyapp/content/task/LetterGraphemeActivity.java
index fae29ad..b58c14b 100644
--- a/app/src/main/java/org/literacyapp/content/task/LetterGraphemeActivity.java
+++ b/app/src/main/java/org/literacyapp/content/task/LetterGraphemeActivity.java
@@ -21,15 +21,11 @@
 import org.literacyapp.dao.VideoDao;
 import org.literacyapp.model.content.Letter;
 import org.literacyapp.model.content.multimedia.Audio;
-import org.literacyapp.model.content.multimedia.JoinVideosWithLetters;
-import org.literacyapp.model.content.multimedia.Video;
 import org.literacyapp.util.MediaPlayerHelper;
 import org.literacyapp.util.MultimediaHelper;
 import org.literacyapp.util.TtsHelper;
 
 import java.io.File;
-import java.util.ArrayList;
-import java.util.List;
 
 public class LetterGraphemeActivity extends AppCompatActivity {
 
@@ -93,28 +89,32 @@ public void onClick(View view) {
             public void onClick(View view) {
                 Log.i(getClass().getName(), "onClick");
 
-                // Look up video(s) containing letter
-                List<Video> videosContainingLetter = new ArrayList<Video>();
-                List<JoinVideosWithLetters> joinVideosWithLettersList = joinVideosWithLettersDao.queryBuilder()
-                        .where(JoinVideosWithLettersDao.Properties.LetterId.eq(letter.getId()))
-                        .list();
-                Log.d(getClass().getName(), "joinVideosWithLettersList.size(): " + joinVideosWithLettersList.size());
-                if (!joinVideosWithLettersList.isEmpty()) {
-                    for (JoinVideosWithLetters joinVideosWithLetters : joinVideosWithLettersList) {
-                        Video video = videoDao.load(joinVideosWithLetters.getVideoId());
-                        Log.d(getClass().getName(), "Adding video with id " + video.getId());
-                        videosContainingLetter.add(video);
-                    }
-                }
-                Log.d(getClass().getName(), "videosContainingLetter.size(): " + videosContainingLetter.size());
-                if (!videosContainingLetter.isEmpty()) {
-                    // Redirect to video(s)
-                    Intent intent = new Intent(getApplicationContext(), VideoActivity.class);
-                    int randomIndex = (int) (Math.random() * videosContainingLetter.size());
-                    Video video = videosContainingLetter.get(randomIndex); // TODO: iterate all videos
-                    intent.putExtra(VideoActivity.EXTRA_KEY_VIDEO_ID, video.getId());
-                    startActivity(intent);
-                }
+//                // Look up video(s) containing letter
+//                List<Video> videosContainingLetter = new ArrayList<Video>();
+//                List<JoinVideosWithLetters> joinVideosWithLettersList = joinVideosWithLettersDao.queryBuilder()
+//                        .where(JoinVideosWithLettersDao.Properties.LetterId.eq(letter.getId()))
+//                        .list();
+//                Log.d(getClass().getName(), "joinVideosWithLettersList.size(): " + joinVideosWithLettersList.size());
+//                if (!joinVideosWithLettersList.isEmpty()) {
+//                    for (JoinVideosWithLetters joinVideosWithLetters : joinVideosWithLettersList) {
+//                        Video video = videoDao.load(joinVideosWithLetters.getVideoId());
+//                        Log.d(getClass().getName(), "Adding video with id " + video.getId());
+//                        videosContainingLetter.add(video);
+//                    }
+//                }
+//                Log.d(getClass().getName(), "videosContainingLetter.size(): " + videosContainingLetter.size());
+//                if (!videosContainingLetter.isEmpty()) {
+//                    // Redirect to video(s)
+//                    Intent intent = new Intent(getApplicationContext(), VideoActivity.class);
+//                    int randomIndex = (int) (Math.random() * videosContainingLetter.size());
+//                    Video video = videosContainingLetter.get(randomIndex); // TODO: iterate all videos
+//                    intent.putExtra(VideoActivity.EXTRA_KEY_VIDEO_ID, video.getId());
+//                    startActivity(intent);
+//                }
+
+                Intent intent = new Intent(getApplicationContext(), SelectLetterActivity.class);
+                intent.putExtra("letter", letter.getText());
+                startActivity(intent);
 
                 finish();
             }
diff --git a/app/src/main/java/org/literacyapp/content/task/SelectLetterActivity.java b/app/src/main/java/org/literacyapp/content/task/SelectLetterActivity.java
new file mode 100644
index 0000000..23322a7
--- /dev/null
+++ b/app/src/main/java/org/literacyapp/content/task/SelectLetterActivity.java
@@ -0,0 +1,307 @@
+package org.literacyapp.content.task;
+
+import android.content.Intent;
+import android.content.res.Resources;
+import android.graphics.Color;
+import android.media.MediaPlayer;
+import android.net.Uri;
+import android.os.Bundle;
+import android.support.v7.app.AppCompatActivity;
+import android.util.Log;
+import android.view.View;
+import android.widget.Button;
+import android.widget.ImageButton;
+
+import com.skyfishjy.library.RippleBackground;
+
+import org.literacyapp.LiteracyApplication;
+import org.literacyapp.R;
+import org.literacyapp.dao.AudioDao;
+import org.literacyapp.dao.JoinVideosWithLettersDao;
+import org.literacyapp.dao.LetterDao;
+import org.literacyapp.dao.VideoDao;
+import org.literacyapp.logic.CurriculumHelper;
+import org.literacyapp.model.Student;
+import org.literacyapp.model.content.Letter;
+import org.literacyapp.model.content.multimedia.Audio;
+import org.literacyapp.model.content.multimedia.JoinVideosWithLetters;
+import org.literacyapp.model.content.multimedia.Video;
+import org.literacyapp.util.MediaPlayerHelper;
+import org.literacyapp.util.MultimediaHelper;
+import org.literacyapp.util.TtsHelper;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
+
+public class SelectLetterActivity extends AppCompatActivity {
+
+    private RippleBackground rippleBackground;
+    private Button listenButton;
+    private Button alt1Button;
+    private Button alt2Button;
+
+    private ImageButton nextButton;
+
+    private LetterDao letterDao;
+    private AudioDao audioDao;
+    private VideoDao videoDao;
+    private JoinVideosWithLettersDao joinVideosWithLettersDao;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        Log.i(getClass().getName(), "onCreate");
+        super.onCreate(savedInstanceState);
+
+        setContentView(R.layout.activity_select_letter);
+
+        rippleBackground = (RippleBackground) findViewById(R.id.rippleBackground);
+        listenButton = (Button) findViewById(R.id.listenButton);
+        alt1Button = (Button) findViewById(R.id.alt1Button);
+        alt2Button = (Button) findViewById(R.id.alt2Button);
+
+        nextButton = (ImageButton) findViewById(R.id.nextButton);
+
+        LiteracyApplication literacyApplication = (LiteracyApplication) getApplicationContext();
+        letterDao = literacyApplication.getDaoSession().getLetterDao();
+        audioDao = literacyApplication.getDaoSession().getAudioDao();
+        videoDao = literacyApplication.getDaoSession().getVideoDao();
+        joinVideosWithLettersDao = literacyApplication.getDaoSession().getJoinVideosWithLettersDao();
+    }
+
+    @Override
+    protected void onStart() {
+        Log.i(getClass().getName(), "onStart");
+        super.onStart();
+
+        String letterExtra = getIntent().getStringExtra("letter");
+        Log.i(getClass().getName(), "letterExtra: " + letterExtra);
+
+        final Letter letter = letterDao.queryBuilder()
+                .where(LetterDao.Properties.Text.eq(letterExtra))
+                .unique();
+        Log.i(getClass().getName(), "letter: " + letter);
+
+        Student student = null;
+        // TODO: get current student
+        List<Letter> availableLetters = new CurriculumHelper(getApplicationContext()).getAvailableLetters(student);
+        ArrayList<String> availableLettersStringArrayList = new ArrayList<>();
+        for (Letter availableLetter : availableLetters) {
+            availableLettersStringArrayList.add(availableLetter.getText());
+        }
+        Log.i(getClass().getName(), "availableLettersStringArrayList: " + availableLettersStringArrayList);
+        availableLettersStringArrayList.remove(letter.getText());
+        Log.i(getClass().getName(), "availableLettersStringArrayList (after removing current letter): " + availableLettersStringArrayList);
+        int randomIndex = (int) (Math.random() * availableLettersStringArrayList.size());
+        String wrongLetterAlternative = availableLettersStringArrayList.get(randomIndex);
+        Log.i(getClass().getName(), "wrongLetterAlternative: " + wrongLetterAlternative);
+        boolean isAlt1Correct = (Math.random() > .5);
+        if (isAlt1Correct) {
+            alt1Button.setText(letter.getText());
+            alt1Button.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    alt1Button.setTextColor(Color.WHITE);
+                    alt1Button.setBackgroundColor(Color.parseColor("#009688"));
+                    alt2Button.setEnabled(false);
+                    MediaPlayerHelper.play(getApplicationContext(), R.raw.alternative_correct);
+                    alt1Button.postDelayed(new Runnable() {
+                        @Override
+                        public void run() {
+                            playLetterSound(letter);
+
+                            rippleBackground.startRippleAnimation();
+                            rippleBackground.postDelayed(new Runnable() {
+                                @Override
+                                public void run() {
+                                    rippleBackground.stopRippleAnimation();
+                                    nextButton.setVisibility(View.VISIBLE);
+                                }
+                            }, 600);
+                        }
+                    }, 1500);
+                }
+            });
+
+            alt2Button.setText(wrongLetterAlternative);
+            alt2Button.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    MediaPlayerHelper.play(getApplicationContext(), R.raw.alternative_incorrect);
+                    alt2Button.postDelayed(new Runnable() {
+                        @Override
+                        public void run() {
+                            playLetterSound(letter);
+
+                            rippleBackground.startRippleAnimation();
+                            rippleBackground.postDelayed(new Runnable() {
+                                @Override
+                                public void run() {
+                                    rippleBackground.stopRippleAnimation();
+                                }
+                            }, 600);
+                        }
+                    }, 1000);
+                }
+            });
+        } else {
+            alt2Button.setText(letter.getText());
+            alt2Button.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    alt2Button.setTextColor(Color.WHITE);
+                    alt2Button.setBackgroundColor(Color.parseColor("#009688"));
+                    alt1Button.setEnabled(false);
+                    MediaPlayerHelper.play(getApplicationContext(), R.raw.alternative_correct);
+                    alt2Button.postDelayed(new Runnable() {
+                        @Override
+                        public void run() {
+                            playLetterSound(letter);
+
+                            rippleBackground.startRippleAnimation();
+                            rippleBackground.postDelayed(new Runnable() {
+                                @Override
+                                public void run() {
+                                    rippleBackground.stopRippleAnimation();
+                                    nextButton.setVisibility(View.VISIBLE);
+                                }
+                            }, 600);
+                        }
+                    }, 1500);
+                }
+            });
+
+            alt1Button.setText(wrongLetterAlternative);
+            alt1Button.setOnClickListener(new View.OnClickListener() {
+                @Override
+                public void onClick(View v) {
+                    MediaPlayerHelper.play(getApplicationContext(), R.raw.alternative_incorrect);
+                    alt1Button.postDelayed(new Runnable() {
+                        @Override
+                        public void run() {
+                            playLetterSound(letter);
+
+                            rippleBackground.startRippleAnimation();
+                            rippleBackground.postDelayed(new Runnable() {
+                                @Override
+                                public void run() {
+                                    rippleBackground.stopRippleAnimation();
+                                }
+                            }, 600);
+                        }
+                    }, 1000);
+                }
+            });
+        }
+
+//        MediaPlayerHelper.play(getApplicationContext(), R.raw.activity_instruction_letter_identification);
+        MediaPlayer mediaPlayer = MediaPlayer.create(getApplicationContext(), R.raw.activity_instruction_letter_identification);
+        mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
+            @Override
+            public void onCompletion(MediaPlayer mediaPlayer) {
+                Log.i(getClass().getName(), "mediaPlayer onCompletion");
+                mediaPlayer.release();
+
+                playLetterSound(letter);
+
+                rippleBackground.startRippleAnimation();
+                rippleBackground.postDelayed(new Runnable() {
+                    @Override
+                    public void run() {
+                        rippleBackground.stopRippleAnimation();
+                    }
+                }, 600);
+            }
+        });
+        mediaPlayer.start();
+
+        listenButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                Log.i(getClass().getName(), "listenButton onClick");
+
+                playLetterSound(letter);
+
+                rippleBackground.startRippleAnimation();
+                rippleBackground.postDelayed(new Runnable() {
+                    @Override
+                    public void run() {
+                        rippleBackground.stopRippleAnimation();
+                    }
+                }, 600);
+            }
+        });
+
+        nextButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                Log.i(getClass().getName(), "onClick");
+
+                // Look up video(s) containing letter
+                List<Video> videosContainingLetter = new ArrayList<Video>();
+                List<JoinVideosWithLetters> joinVideosWithLettersList = joinVideosWithLettersDao.queryBuilder()
+                        .where(JoinVideosWithLettersDao.Properties.LetterId.eq(letter.getId()))
+                        .list();
+                Log.d(getClass().getName(), "joinVideosWithLettersList.size(): " + joinVideosWithLettersList.size());
+                if (!joinVideosWithLettersList.isEmpty()) {
+                    for (JoinVideosWithLetters joinVideosWithLetters : joinVideosWithLettersList) {
+                        Video video = videoDao.load(joinVideosWithLetters.getVideoId());
+                        Log.d(getClass().getName(), "Adding video with id " + video.getId());
+                        videosContainingLetter.add(video);
+                    }
+                }
+                Log.d(getClass().getName(), "videosContainingLetter.size(): " + videosContainingLetter.size());
+                if (!videosContainingLetter.isEmpty()) {
+                    // Redirect to video(s)
+                    Intent intent = new Intent(getApplicationContext(), VideoActivity.class);
+                    int randomIndex = (int) (Math.random() * videosContainingLetter.size());
+                    Video video = videosContainingLetter.get(randomIndex); // TODO: iterate all videos
+                    intent.putExtra(VideoActivity.EXTRA_KEY_VIDEO_ID, video.getId());
+                    startActivity(intent);
+                }
+
+                finish();
+            }
+        });
+    }
+
+    private void playLetterSound(Letter letter) {
+        Log.i(getClass().getName(), "playLetterSound");
+
+        // Look up corresponding Audio
+        Log.d(getClass().getName(), "Looking up \"letter_sound_" + letter.getText() + "\"");
+        final Audio audio = audioDao.queryBuilder()
+                .where(AudioDao.Properties.Transcription.eq("letter_sound_" + letter.getText()))
+                .unique();
+        Log.i(getClass().getName(), "audio: " + audio);
+        if (audio != null) {
+            // Play audio
+            File audioFile = MultimediaHelper.getFile(audio);
+            Uri uri = Uri.parse(audioFile.getAbsolutePath());
+            MediaPlayer mediaPlayer = MediaPlayer.create(getApplicationContext(), uri);
+            mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
+                @Override
+                public void onCompletion(MediaPlayer mediaPlayer) {
+                    Log.i(getClass().getName(), "mediaPlayer onCompletion");
+                    mediaPlayer.release();
+                }
+            });
+            mediaPlayer.start();
+        } else {
+            // Audio not found. Fall-back to application resource.
+            String audioFileName = "letter_sound_" + letter.getText();
+            int resourceId = getResources().getIdentifier(audioFileName, "raw", getPackageName());
+            try {
+                if (resourceId != 0) {
+                    MediaPlayerHelper.play(getApplicationContext(), resourceId);
+                } else {
+                    // Fall-back to TTS
+                    TtsHelper.speak(getApplicationContext(), letter.getText());
+                }
+            } catch (Resources.NotFoundException e) {
+                // Fall-back to TTS
+                TtsHelper.speak(getApplicationContext(), letter.getText());
+            }
+        }
+    }
+}
diff --git a/app/src/main/java/org/literacyapp/dao/DaoMaster.java b/app/src/main/java/org/literacyapp/dao/DaoMaster.java
index 88544b5..234a46c 100644
--- a/app/src/main/java/org/literacyapp/dao/DaoMaster.java
+++ b/app/src/main/java/org/literacyapp/dao/DaoMaster.java
@@ -14,10 +14,10 @@
 
 // THIS CODE IS GENERATED BY greenDAO, DO NOT EDIT.
 /**
- * Master of DAO (schema version 1004000): knows all DAOs.
+ * Master of DAO (schema version 1004001): knows all DAOs.
  */
 public class DaoMaster extends AbstractDaoMaster {
-    public static final int SCHEMA_VERSION = 1004000;
+    public static final int SCHEMA_VERSION = 1004001;
 
     /** Creates underlying database table using DAOs. */
     public static void createAllTables(Database db, boolean ifNotExists) {
diff --git a/app/src/main/res/drawable/button_default.xml b/app/src/main/res/drawable/button_default.xml
index 3da24ff..229e2fe 100644
--- a/app/src/main/res/drawable/button_default.xml
+++ b/app/src/main/res/drawable/button_default.xml
@@ -4,11 +4,11 @@
 
     <corners android:radius="1000dp" />
 
-    <solid android:color="@color/colorPrimary" />
+    <solid android:color="@color/colorAccent" />
 
     <stroke
         android:width="2dip"
-        android:color="@color/colorPrimaryDark" />
+        android:color="@color/colorAccentDark" />
 
     <padding
         android:bottom="4dp"
diff --git a/app/src/main/res/drawable/button_focused.xml b/app/src/main/res/drawable/button_focused.xml
index 7d896bd..eba404d 100644
--- a/app/src/main/res/drawable/button_focused.xml
+++ b/app/src/main/res/drawable/button_focused.xml
@@ -3,10 +3,10 @@
     android:shape="oval">
 
     <corners android:radius="1000dp" />
-    <solid android:color="@color/colorPrimary" />
+    <solid android:color="@color/colorAccent" />
     <stroke
         android:width="4dip"
-        android:color="@color/colorPrimaryDark" />
+        android:color="@color/colorAccentDark" />
     <padding
         android:bottom="4dp"
         android:left="4dp"
diff --git a/app/src/main/res/drawable/button_pressed.xml b/app/src/main/res/drawable/button_pressed.xml
index 7b2129b..9390efe 100644
--- a/app/src/main/res/drawable/button_pressed.xml
+++ b/app/src/main/res/drawable/button_pressed.xml
@@ -3,10 +3,10 @@
     android:shape="oval">
 
     <corners android:radius="1000dp" />
-    <solid android:color="@color/colorPrimary" />
+    <solid android:color="@color/colorAccent" />
     <stroke
         android:width="6dip"
-        android:color="@color/colorPrimaryDark" />
+        android:color="@color/colorAccentDark" />
     <padding
         android:bottom="4dp"
         android:left="4dp"
diff --git a/app/src/main/res/drawable/ic_hearing_black_64dp.xml b/app/src/main/res/drawable/ic_hearing_black_64dp.xml
new file mode 100644
index 0000000..05a1dcf
--- /dev/null
+++ b/app/src/main/res/drawable/ic_hearing_black_64dp.xml
@@ -0,0 +1,4 @@
+<vector android:height="64dp" android:viewportHeight="24.0"
+    android:viewportWidth="24.0" android:width="64dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M17,20c-0.29,0 -0.56,-0.06 -0.76,-0.15 -0.71,-0.37 -1.21,-0.88 -1.71,-2.38 -0.51,-1.56 -1.47,-2.29 -2.39,-3 -0.79,-0.61 -1.61,-1.24 -2.32,-2.53C9.29,10.98 9,9.93 9,9c0,-2.8 2.2,-5 5,-5s5,2.2 5,5h2c0,-3.93 -3.07,-7 -7,-7S7,5.07 7,9c0,1.26 0.38,2.65 1.07,3.9 0.91,1.65 1.98,2.48 2.85,3.15 0.81,0.62 1.39,1.07 1.71,2.05 0.6,1.82 1.37,2.84 2.73,3.55 0.51,0.23 1.07,0.35 1.64,0.35 2.21,0 4,-1.79 4,-4h-2c0,1.1 -0.9,2 -2,2zM7.64,2.64L6.22,1.22C4.23,3.21 3,5.96 3,9s1.23,5.79 3.22,7.78l1.41,-1.41C6.01,13.74 5,11.49 5,9s1.01,-4.74 2.64,-6.36zM11.5,9c0,1.38 1.12,2.5 2.5,2.5s2.5,-1.12 2.5,-2.5 -1.12,-2.5 -2.5,-2.5 -2.5,1.12 -2.5,2.5z"/>
+</vector>
diff --git a/app/src/main/res/layout/activity_letter_grapheme.xml b/app/src/main/res/layout/activity_letter_grapheme.xml
index 701f486..6b8ed08 100644
--- a/app/src/main/res/layout/activity_letter_grapheme.xml
+++ b/app/src/main/res/layout/activity_letter_grapheme.xml
@@ -23,5 +23,5 @@
         android:layout_alignParentRight="true"
         android:src="@drawable/ic_arrow_forward_black_24dp"
         style="?android:attr/buttonBarButtonStyle"
-        android:tint="@color/blue" />
+        android:tint="@color/colorAccent" />
 </RelativeLayout>
diff --git a/app/src/main/res/layout/activity_loading.xml b/app/src/main/res/layout/activity_loading.xml
index 1760ca1..09accd7 100644
--- a/app/src/main/res/layout/activity_loading.xml
+++ b/app/src/main/res/layout/activity_loading.xml
@@ -20,5 +20,5 @@
         android:layout_alignParentRight="true"
         android:src="@drawable/ic_arrow_forward_black_24dp"
         style="?android:attr/buttonBarButtonStyle"
-        android:tint="@color/blue" />
+        android:tint="@color/colorAccent" />
 </RelativeLayout>
diff --git a/app/src/main/res/layout/activity_number_grapheme.xml b/app/src/main/res/layout/activity_number_grapheme.xml
index e09cb20..aa32adb 100644
--- a/app/src/main/res/layout/activity_number_grapheme.xml
+++ b/app/src/main/res/layout/activity_number_grapheme.xml
@@ -23,5 +23,5 @@
         android:layout_alignParentRight="true"
         android:src="@drawable/ic_arrow_forward_black_24dp"
         style="?android:attr/buttonBarButtonStyle"
-        android:tint="@color/blue" />
+        android:tint="@color/colorAccent" />
 </RelativeLayout>
diff --git a/app/src/main/res/layout/activity_select_letter.xml b/app/src/main/res/layout/activity_select_letter.xml
new file mode 100644
index 0000000..045314e
--- /dev/null
+++ b/app/src/main/res/layout/activity_select_letter.xml
@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="utf-8"?>
+<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:paddingBottom="@dimen/activity_vertical_margin"
+    android:paddingLeft="@dimen/activity_horizontal_margin"
+    android:paddingRight="@dimen/activity_horizontal_margin"
+    android:paddingTop="@dimen/activity_vertical_margin"
+    tools:context=".content.task.VisemeActivity">
+
+    <LinearLayout
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_centerInParent="true"
+        android:orientation="vertical">
+
+        <!-- RippleBackground extends RelativeLayout -->
+        <com.skyfishjy.library.RippleBackground
+            xmlns:android="http://schemas.android.com/apk/res/android"
+            xmlns:app="http://schemas.android.com/apk/res-auto"
+            android:id="@+id/rippleBackground"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:gravity="center"
+            app:rb_color="#DDD"
+            app:rb_radius="128dp"
+            app:rb_rippleAmount="1"
+            app:rb_duration="600"
+            app:rb_scale="2">
+
+            <Button
+                android:id="@+id/listenButton"
+                android:layout_width="128dp"
+                android:layout_height="128dp"
+                android:layout_centerInParent="true"
+                android:background="@drawable/button_custom"
+                android:paddingTop="32dp"
+                android:drawableTop="@drawable/ic_hearing_black_64dp"
+                android:drawableTint="#CCFFFFFF" />
+        </com.skyfishjy.library.RippleBackground>
+
+        <LinearLayout
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/activity_vertical_margin">
+
+            <Button
+                android:id="@+id/alt1Button"
+                android:layout_width="256dp"
+                android:layout_height="256dp"
+                android:text="a"
+                android:textSize="96sp"
+                android:textAllCaps="false" />
+            <Button
+                android:id="@+id/alt2Button"
+                android:layout_width="256dp"
+                android:layout_height="256dp"
+                android:text="i"
+                android:textSize="96sp"
+                android:textAllCaps="false" />
+        </LinearLayout>
+    </LinearLayout>
+
+    <ImageButton android:id="@+id/nextButton"
+        android:layout_width="96dp"
+        android:layout_height="96dp"
+        android:visibility="gone"
+        android:scaleType="fitXY"
+        android:layout_alignParentBottom="true"
+        android:layout_alignParentRight="true"
+        android:src="@drawable/ic_arrow_forward_black_24dp"
+        style="?android:attr/buttonBarButtonStyle"
+        android:tint="@color/colorAccent" />
+</RelativeLayout>
diff --git a/app/src/main/res/raw/alternative_correct.wav b/app/src/main/res/raw/alternative_correct.wav
new file mode 100644
index 0000000..5b3aba7
Binary files /dev/null and b/app/src/main/res/raw/alternative_correct.wav differ
diff --git a/app/src/main/res/raw/alternative_incorrect.wav b/app/src/main/res/raw/alternative_incorrect.wav
new file mode 100644
index 0000000..bdd516d
Binary files /dev/null and b/app/src/main/res/raw/alternative_incorrect.wav differ
diff --git a/app/src/main/res/values/colors.xml b/app/src/main/res/values/colors.xml
index df444c0..f049b8c 100644
--- a/app/src/main/res/values/colors.xml
+++ b/app/src/main/res/values/colors.xml
@@ -3,6 +3,7 @@
     <color name="colorPrimary">#4CAF50</color>
     <color name="colorPrimaryDark">#409343</color>
     <color name="colorAccent">#009688</color>
+    <color name="colorAccentDark">#008074</color>
 
     <color name="black_overlay">#66000000</color>