The following is found in Android 2.3.3 source code git:
501 <activity android:name="VoiceInputOutputSettings"
502 android:label="@string/voice_input_output_settings">
503 <intent-filter>
504 <action android:name="android.intent.action.MAIN" />
505 <action android:name="com.android.settings.VOICE_INPUT_OUTPUT_SETTINGS" />
506 <category android:name="android.intent.category.DEFAULT" />
507 </intent-filter>
508 </activity>
509
510 <activity android:name="TextToSpeechSettings" android:label="@string/tts_settings">
511 <intent-filter>
512 <action android:name="android.intent.action.MAIN" />
513 <action android:name="com.android.settings.TTS_SETTINGS" />
514 <category android:name="android.intent.category.DEFAULT" />
515 </intent-filter>
516 </activity>
There may not be official constant for these two actions. But you can try "com.android.settings.VOICE_INPUT_OUTPUT_SETTINGS" and "com.android.settings.TTS_SETTINGS", it works on my Nexus S.