diff --git a/tools/chatgui-android/app/src/main/res/values-ru/strings.xml b/tools/chatgui-android/app/src/main/res/values-ru/strings.xml
index fbdb5589..b18aa2d8 100644
--- a/tools/chatgui-android/app/src/main/res/values-ru/strings.xml
+++ b/tools/chatgui-android/app/src/main/res/values-ru/strings.xml
@@ -48,6 +48,9 @@
     <string name="radio_member_mute">Не слушать этого участника в рации</string>
     <string name="radio_member_listen">Слушать этого участника в рации</string>
     <string name="radio_member_mute_failed">Не удалось изменить настройку прослушивания рации</string>
+    <string name="radio_member_silent">Рация: молчит</string>
+    <string name="radio_member_speaking">Рация: говорит</string>
+    <string name="radio_member_muted">Рация: заглушён</string>
     <string name="radio_notification">"Рация: PTT / автоматическая передача по голосу"</string>
     <string name="overlay_stopped">"Плавающая кнопка остановлена"</string>
     <string name="ongoing_call">"Текущий звонок"</string>
diff --git a/tools/chatgui-android/app/src/main/res/values/strings.xml b/tools/chatgui-android/app/src/main/res/values/strings.xml
index 319394a6..bb3552d7 100644
--- a/tools/chatgui-android/app/src/main/res/values/strings.xml
+++ b/tools/chatgui-android/app/src/main/res/values/strings.xml
@@ -48,6 +48,9 @@
     <string name="radio_member_mute">Mute this member in radio</string>
     <string name="radio_member_listen">Listen to this member in radio</string>
     <string name="radio_member_mute_failed">Cannot change radio listening setting</string>
+    <string name="radio_member_silent">Radio: silent</string>
+    <string name="radio_member_speaking">Radio: speaking</string>
+    <string name="radio_member_muted">Radio: muted</string>
     <string name="radio_notification">"Radio: PTT / automatic voice transmission"</string>
     <string name="overlay_stopped">"Floating button stopped"</string>
     <string name="ongoing_call">"Ongoing call"</string>
diff --git a/tools/chatgui-android/app/src/test/java/com/utun/chat/data/RadioTalkStateTest.kt b/tools/chatgui-android/app/src/test/java/com/utun/chat/data/RadioTalkStateTest.kt
new file mode 100644
index 00000000..b3ae8863
--- /dev/null
+++ b/tools/chatgui-android/app/src/test/java/com/utun/chat/data/RadioTalkStateTest.kt
@@ -0,0 +1,52 @@
+package com.utun.chat.data
+
+import org.junit.Assert.*
+import org.junit.Test
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+
+class RadioTalkStateTest {
+    private fun event(group: Long = 7, node: Long = 42, on: Boolean = true): RadioTalkEvent {
+        val bytes = ByteBuffer.allocate(19).order(ByteOrder.LITTLE_ENDIAN)
+            .putLong(group).putLong(node).putShort(65535.toShort()).put(if (on) 1.toByte() else 0.toByte()).array()
+        return requireNotNull(parseRadioTalkEvent(bytes))
+    }
+
+    @Test fun stopRemovesOnlyItsSourceAndMuteDoesNotSuppressSpeech() {
+        var state = RadioTalkState(7).onTalk(event()).onTalk(event(node = 43))
+        assertEquals(setOf(42L, 43L), state.speakers)
+        val muted = ChatMember(42, "Alice", radioMuted = true)
+        assertTrue(muted.radioMuted && muted.nodeId in state.speakers)
+        assertSame(state, state.onTalk(event()))
+        state = state.onTalk(event(on = false))
+        assertEquals(setOf(43L), state.speakers)
+        assertSame(state, state.onTalk(event(on = false)))
+        assertTrue(state.onTalk(event(node = 43, on = false)).speakers.isEmpty())
+    }
+
+    @Test fun activeGroupOwnsSpeakersIndependentlyOfDisplayedMemberSnapshots() {
+        val group = 0xfedcba9876543210uL.toLong()
+        val state = RadioTalkState(group).onTalk(event(group))
+        assertEquals(setOf(42L), state.speakers)
+        assertSame(state, state.onTalk(event(group = 8)))
+        assertSame(state, state.onTalk(event(group = 8, on = false)))
+        val refreshed = ChatMember(42, "Updated", radioActive = false, radioMuted = true)
+        assertTrue(refreshed.nodeId in state.speakers)
+        val switched = RadioTalkState(8)
+        assertSame(switched, switched.onTalk(event(group)))
+        val stopped = RadioTalkState()
+        assertSame(stopped, stopped.onTalk(event(group)))
+        assertTrue(RadioTalkState(group).speakers.isEmpty())
+    }
+
+    @Test fun malformedEventsCannotChangeTheSpeakerState() {
+        assertNull(parseRadioTalkEvent(null)); assertNull(parseRadioTalkEvent(ByteArray(18)))
+        assertNull(parseRadioTalkEvent(ByteArray(20))); assertNull(parseRadioTalkEvent(ByteArray(19)))
+        val bytes = ByteBuffer.allocate(19).order(ByteOrder.LITTLE_ENDIAN).putLong(7).putLong(42).putShort(1).put(2).array()
+        assertNull(parseRadioTalkEvent(bytes))
+        bytes[18] = 1
+        assertEquals(1, requireNotNull(parseRadioTalkEvent(bytes)).stream)
+        assertEquals(65535, event().stream)
+        assertNull(parseRadioTalkEvent(ByteBuffer.wrap(bytes).order(ByteOrder.LITTLE_ENDIAN).putLong(0, 0).array()))
+    }
+}