diff --git a/litellm/router.py b/litellm/router.py
index a3c3afa9326..ae5faca7ba6 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -2736,7 +2736,7 @@ class Router:
                 self.fail_calls[model_name] += 1
             raise e
 
-    async def aspeech(self, model: str, input: str, voice: str, **kwargs):
+    async def aspeech(self, model: str, input: str, voice: Optional[str] = None, **kwargs):
         """
         Example Usage:
 
@@ -2770,7 +2770,14 @@ class Router:
         """
         try:
             kwargs["input"] = input
-            kwargs["voice"] = voice
+            if voice is not None:
+                kwargs["voice"] = voice
+            
+            extra_body = kwargs.pop("extra_body", None)
+            if isinstance(extra_body, dict):
+                for k, v in extra_body.items():
+                    if k not in kwargs:
+                        kwargs[k] = v
 
             deployment = await self.async_get_available_deployment(
                 model=model,
diff --git a/tests/test_litellm/test_router_aspeech_extra_body.py b/tests/test_litellm/test_router_aspeech_extra_body.py
new file mode 100644
index 00000000000..3f22b3fc18e
--- /dev/null
+++ b/tests/test_litellm/test_router_aspeech_extra_body.py
@@ -0,0 +1,126 @@
+import asyncio
+from typing import Any, Dict
+
+import litellm
+
+
+class DummyRouter:
+    """
+    Minimal stand-in for Router to test the aspeech method in isolation.
+    It has only the attributes and methods that aspeech uses.
+    """
+
+    def __init__(self) -> None:
+        self.default_litellm_params = {}
+
+    async def async_get_available_deployment(
+        self,
+        model: str,
+        messages,
+        specific_deployment=None,
+        request_kwargs=None,
+    ):
+        # Return a minimal deployment dict with litellm_params
+        return {
+            "litellm_params": {
+                "model": model,
+            }
+        }
+
+    def _update_kwargs_before_fallbacks(self, model: str, kwargs: Dict[str, Any]) -> None:
+        # No-op for this test
+        return
+
+    def _get_client(self, deployment, kwargs: Dict[str, Any], client_type: str):
+        # No client needed for this test
+        return None
+
+    async def aspeech(self, model: str, input: str, voice=None, **kwargs):
+        # This body should match the aspeech implementation you modified in router.py
+        try:
+            kwargs["input"] = input
+
+            if voice is not None:
+                kwargs["voice"] = voice
+
+            extra_body = kwargs.pop("extra_body", None)
+            if isinstance(extra_body, dict):
+                for k, v in extra_body.items():
+                    if k not in kwargs:
+                        kwargs[k] = v
+
+            deployment = await self.async_get_available_deployment(
+                model=model,
+                messages=[{"role": "user", "content": "prompt"}],
+                specific_deployment=kwargs.pop("specific_deployment", None),
+                request_kwargs=kwargs,
+            )
+            self._update_kwargs_before_fallbacks(model=model, kwargs=kwargs)
+            data = deployment["litellm_params"].copy()
+            data["model"]  # keep same side effect as real code
+
+            for k, v in self.default_litellm_params.items():
+                if k not in kwargs:
+                    kwargs[k] = v
+                elif k == "metadata":
+                    kwargs[k].update(v)
+
+            # litellm.aspeech will be mocked in the test
+            response = await litellm.aspeech(
+                **{
+                    **data,
+                    "client": None,
+                    **kwargs,
+                }
+            )
+            return response
+        except Exception as e:
+            raise e
+
+
+async def _call_aspeech_with_extra_body(monkeypatch):
+    captured_kwargs: Dict[str, Any] = {}
+
+    async def mock_aspeech(**kwargs):
+        nonlocal captured_kwargs
+        captured_kwargs = kwargs
+        class DummyResponse:
+            pass
+        return DummyResponse()
+
+    # Patch litellm.aspeech so we don't make real API calls
+    monkeypatch.setattr(litellm, "aspeech", mock_aspeech)
+
+    router = DummyRouter()
+
+    extra_body = {
+        "ref_audio": "dummy-audio",
+        "ref_text": "dummy-text",
+        "task_type": "Base",
+    }
+
+    # Call aspeech without voice, but with extra_body
+    await router.aspeech(
+        model="qwen3-tts",
+        input="hello world",
+        extra_body=extra_body,
+    )
+
+    return captured_kwargs
+
+
+def test_aspeech_forwards_extra_body(monkeypatch):
+    """
+    Ensure aspeech forwards extra_body fields (e.g. ref_audio, ref_text, task_type)
+    to litellm.aspeech, even when voice is omitted.
+    """
+    captured_kwargs = asyncio.run(_call_aspeech_with_extra_body(monkeypatch))
+
+    # Standard fields should be present
+    assert captured_kwargs["model"] == "qwen3-tts"
+    assert captured_kwargs["input"] == "hello world"
+
+    # Custom fields from extra_body must also be present
+    assert captured_kwargs["ref_audio"] == "dummy-audio"
+    assert captured_kwargs["ref_text"] == "dummy-text"
+    assert captured_kwargs["task_type"] == "Base"