diff --git a/bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/DialogProcessor.java b/bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/DialogProcessor.java
index d721ffc722..0d72ad899d 100644
--- a/bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/DialogProcessor.java
+++ b/bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/DialogProcessor.java
@@ -121,7 +121,7 @@ public class DialogProcessor implements KSListener, STTListener {
         this.bundle = bundle;
         this.ksFormat = VoiceManagerImpl.getBestMatch(source.getSupportedFormats(), ks.getSupportedFormats());
         this.sttFormat = VoiceManagerImpl.getBestMatch(source.getSupportedFormats(), stt.getSupportedFormats());
-        this.ttsFormat = VoiceManagerImpl.getBestMatch(sink.getSupportedFormats(), tts.getSupportedFormats());
+        this.ttsFormat = VoiceManagerImpl.getBestMatch(tts.getSupportedFormats(), sink.getSupportedFormats());
     }
 
     public void start() {
diff --git a/bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/VoiceManagerImpl.java b/bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/VoiceManagerImpl.java
index cbf3284e85..64c16a1f42 100644
--- a/bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/VoiceManagerImpl.java
+++ b/bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/VoiceManagerImpl.java
@@ -225,19 +225,19 @@ public class VoiceManagerImpl implements VoiceManager, ConfigOptionProvider {
                 throw new TTSException(
                         "Unable to find a voice for language " + localeProvider.getLocale().getLanguage());
             }
-            Set<AudioFormat> sttAudioFormats = tts.getSupportedFormats();
+            Set<AudioFormat> ttsSupportedFormats = tts.getSupportedFormats();
             AudioSink sink = audioManager.getSink(sinkId);
             if (sink == null) {
                 throw new TTSException("Unable to find the audio sink " + sinkId);
             }
 
-            AudioFormat sttAudioFormat = getBestMatch(sink.getSupportedFormats(), sttAudioFormats);
-            if (sttAudioFormat == null) {
+            AudioFormat ttsAudioFormat = getBestMatch(ttsSupportedFormats, sink.getSupportedFormats());
+            if (ttsAudioFormat == null) {
                 throw new TTSException("No compatible audio format found for TTS '" + tts.getId() + "' and sink '"
                         + sink.getId() + "'");
             }
 
-            AudioStream audioStream = tts.synthesize(text, voice, sttAudioFormat);
+            AudioStream audioStream = tts.synthesize(text, voice, ttsAudioFormat);
             if (!sink.getSupportedStreams().stream().anyMatch(clazz -> clazz.isInstance(audioStream))) {
                 throw new TTSException(
                         "Failed playing audio stream '" + audioStream + "' as audio sink doesn't support it");
@@ -503,8 +503,9 @@ public class VoiceManagerImpl implements VoiceManager, ConfigOptionProvider {
         if (ksService == null || sttService == null || ttsService == null || interpreter == null || audioSource == null
                 || audioSink == null || b == null) {
             throw new IllegalStateException("Cannot start dialog as services are missing.");
-        } else if (!ksService.getSupportedLocales().contains(loc) || !sttService.getSupportedLocales().contains(loc)
-                || !interpreter.getSupportedLocales().contains(loc)) {
+        } else if (!checkLocales(ksService.getSupportedLocales(), loc)
+                || !checkLocales(sttService.getSupportedLocales(), loc)
+                || !checkLocales(interpreter.getSupportedLocales(), loc)) {
             throw new IllegalStateException("Cannot start dialog as provided locale is not supported by all services.");
         } else {
             DialogProcessor processor = dialogProcessors.get(audioSource.getId());
@@ -548,6 +549,18 @@ public class VoiceManagerImpl implements VoiceManager, ConfigOptionProvider {
         dialogProcessors.clear();
     }
 
+    private boolean checkLocales(@Nullable Set<Locale> supportedLocales, Locale locale) {
+        if (supportedLocales == null) {
+            // rule interpreter returns null so allowing it
+            return true;
+        }
+        return supportedLocales.stream().anyMatch(sLocale -> {
+            var country = sLocale.getCountry();
+            return Objects.equals(sLocale.getLanguage(), locale.getLanguage())
+                    && (country == null || country.isBlank() || country.equals(locale.getCountry()));
+        });
+    }
+
     @Reference(cardinality = ReferenceCardinality.MULTIPLE, policy = ReferencePolicy.DYNAMIC)
     protected void addKSService(KSService ksService) {
         this.ksServices.put(ksService.getId(), ksService);