diff --git a/backend/app/main.py b/backend/app/main.py
index 90d8a79..cbd993d 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -68,6 +68,14 @@ async def _start_model_reaper():
             except Exception:
                 logger.exception("Model reaper encountered an error")
 
+    # Log eviction configuration at startup
+    logger.info(
+        "Model Eviction -> enabled: %s | idle_timeout: %ss | check_interval: %ss",
+        getattr(config, "MODEL_EVICTION_ENABLED", True),
+        getattr(config, "MODEL_IDLE_TIMEOUT_SECONDS", 0),
+        getattr(config, "MODEL_IDLE_CHECK_INTERVAL_SECONDS", 60),
+    )
+
     app.state._model_reaper_task = asyncio.create_task(reaper())
 
 
diff --git a/backend/start_server.py b/backend/start_server.py
index 3b7a82c..76c899f 100644
--- a/backend/start_server.py
+++ b/backend/start_server.py
@@ -14,6 +14,14 @@ if __name__ == "__main__":
     print(f"CORS Origins: {config.CORS_ORIGINS}")
     print(f"Project Root: {config.PROJECT_ROOT}")
     print(f"Device: {config.DEVICE}")
+    # Idle eviction settings
+    print(
+        "Model Eviction -> enabled: {} | idle_timeout: {}s | check_interval: {}s".format(
+            getattr(config, "MODEL_EVICTION_ENABLED", True),
+            getattr(config, "MODEL_IDLE_TIMEOUT_SECONDS", 0),
+            getattr(config, "MODEL_IDLE_CHECK_INTERVAL_SECONDS", 60),
+        )
+    )
     
     uvicorn.run(
         "app.main:app",
diff --git a/frontend/js/app.js b/frontend/js/app.js
index a0d9981..18f5a88 100644
--- a/frontend/js/app.js
+++ b/frontend/js/app.js
@@ -1,6 +1,10 @@
 import { getSpeakers, addSpeaker, deleteSpeaker, generateDialog } from './api.js';
 import { API_BASE_URL, API_BASE_URL_FOR_FILES } from './config.js';
 
+// Shared per-line audio playback state to prevent overlapping playback
+let currentLineAudio = null;
+let currentLineAudioBtn = null;
+
 // --- Global Inline Notification Helpers --- //
 const noticeEl = document.getElementById('global-notice');
 const noticeContentEl = document.getElementById('global-notice-content');
@@ -399,10 +403,46 @@ async function initializeDialogEditor() {
             playBtn.disabled = !item.audioUrl;
             playBtn.onclick = () => {
                 if (!item.audioUrl) return;
-                let audioUrl = item.audioUrl.startsWith('http') ? item.audioUrl : `${API_BASE_URL_FOR_FILES}${item.audioUrl}`;
-                // Use a shared audio element or create one per play
-                let audio = new window.Audio(audioUrl);
-                audio.play();
+                const audioUrl = item.audioUrl.startsWith('http') ? item.audioUrl : `${API_BASE_URL_FOR_FILES}${item.audioUrl}`;
+
+                // If something is already playing
+                if (currentLineAudio && !currentLineAudio.paused) {
+                    if (currentLineAudioBtn === playBtn) {
+                        // Same line: ignore click to prevent overlapping
+                        return;
+                    }
+                    // Stop previous audio and re-enable its button
+                    try {
+                        currentLineAudio.pause();
+                        currentLineAudio.currentTime = 0;
+                    } catch (e) { /* noop */ }
+                    if (currentLineAudioBtn) {
+                        try { currentLineAudioBtn.disabled = false; } catch (e) { /* detached */ }
+                    }
+                }
+
+                const audio = new window.Audio(audioUrl);
+                currentLineAudio = audio;
+                currentLineAudioBtn = playBtn;
+                // Disable this play button while playing
+                playBtn.disabled = true;
+
+                const clearState = () => {
+                    if (currentLineAudio === audio) {
+                        currentLineAudio = null;
+                        currentLineAudioBtn = null;
+                    }
+                    try { playBtn.disabled = false; } catch (e) { /* detached */ }
+                };
+
+                audio.addEventListener('ended', clearState, { once: true });
+                audio.addEventListener('error', clearState, { once: true });
+
+                audio.play().catch(err => {
+                    console.error('Audio play failed:', err);
+                    clearState();
+                    showNotice('Could not play audio.', 'error', { timeout: 2000 });
+                });
             };
             actionsTd.appendChild(playBtn);