diff --git a/src/pipecat/services/aws/llm.py b/src/pipecat/services/aws/llm.py
index bf226d815..5420addf0 100644
--- a/src/pipecat/services/aws/llm.py
+++ b/src/pipecat/services/aws/llm.py
@@ -67,7 +67,7 @@ class AWSBedrockLLMSettings(LLMSettings):
     """
 
     stop_sequences: list[str] | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    latency: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    latency: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     enable_prompt_caching: bool | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     additional_model_request_fields: dict[str, Any] | _NotGiven = field(
         default_factory=lambda: NOT_GIVEN
diff --git a/src/pipecat/services/aws/tts.py b/src/pipecat/services/aws/tts.py
index 93919c860..d49aa796a 100644
--- a/src/pipecat/services/aws/tts.py
+++ b/src/pipecat/services/aws/tts.py
@@ -133,11 +133,11 @@ class AWSPollyTTSSettings(TTSSettings):
         lexicon_names: List of pronunciation lexicons to apply.
     """
 
-    engine: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    pitch: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    rate: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    volume: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    lexicon_names: list[str] | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    engine: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    pitch: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    rate: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    volume: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    lexicon_names: list[str] | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
 
 
 class AWSPollyTTSService(TTSService):
diff --git a/src/pipecat/services/azure/tts.py b/src/pipecat/services/azure/tts.py
index 46811a1a3..4e6879d1a 100644
--- a/src/pipecat/services/azure/tts.py
+++ b/src/pipecat/services/azure/tts.py
@@ -80,13 +80,13 @@ class AzureTTSSettings(TTSSettings):
         volume: Volume level (e.g., "+20%", "loud", "x-soft").
     """
 
-    emphasis: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    pitch: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    rate: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    role: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    style: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    style_degree: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    volume: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    emphasis: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    pitch: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    rate: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    role: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    style: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    style_degree: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    volume: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
 
 
 class AzureBaseTTSService:
diff --git a/src/pipecat/services/google/gemini_live/llm.py b/src/pipecat/services/google/gemini_live/llm.py
index b4ced161f..7c0c22933 100644
--- a/src/pipecat/services/google/gemini_live/llm.py
+++ b/src/pipecat/services/google/gemini_live/llm.py
@@ -342,7 +342,7 @@ class GeminiLiveLLMSettings(LLMSettings):
     modalities: GeminiModalities | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     language: Language | str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     media_resolution: GeminiMediaResolution | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    vad: GeminiVADParams | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    vad: GeminiVADParams | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     context_window_compression: ContextWindowCompressionParams | dict | _NotGiven = field(
         default_factory=lambda: NOT_GIVEN
     )
diff --git a/src/pipecat/services/google/llm.py b/src/pipecat/services/google/llm.py
index e5e4fd5b6..faba2868b 100644
--- a/src/pipecat/services/google/llm.py
+++ b/src/pipecat/services/google/llm.py
@@ -107,7 +107,7 @@ class GoogleLLMSettings(LLMSettings):
         thinking: Thinking configuration.
     """
 
-    thinking: Union["GoogleLLMService.ThinkingConfig", _NotGiven] = field(
+    thinking: Union["GoogleLLMService.ThinkingConfig", None, _NotGiven] = field(
         default_factory=lambda: NOT_GIVEN
     )
 
diff --git a/src/pipecat/services/google/stt.py b/src/pipecat/services/google/stt.py
index b34056ee2..d9fb0a160 100644
--- a/src/pipecat/services/google/stt.py
+++ b/src/pipecat/services/google/stt.py
@@ -385,7 +385,7 @@ class GoogleSTTSettings(STTSettings):
     """
 
     languages: list[Language] | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    language_codes: list[str] | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    language_codes: list[str] | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     use_separate_recognition_per_channel: bool | _NotGiven = field(
         default_factory=lambda: NOT_GIVEN
     )
diff --git a/src/pipecat/services/inworld/tts.py b/src/pipecat/services/inworld/tts.py
index 33c332384..ef3f0f956 100644
--- a/src/pipecat/services/inworld/tts.py
+++ b/src/pipecat/services/inworld/tts.py
@@ -72,8 +72,8 @@ class InworldTTSSettings(TTSSettings):
         temperature: Temperature for speech synthesis.
     """
 
-    speaking_rate: float | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    temperature: float | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    speaking_rate: float | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    temperature: float | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
 
     _aliases: ClassVar[dict[str, str]] = {
         "voiceId": "voice",
diff --git a/src/pipecat/services/openai/tts.py b/src/pipecat/services/openai/tts.py
index 66f027c8d..a0e6a93dd 100644
--- a/src/pipecat/services/openai/tts.py
+++ b/src/pipecat/services/openai/tts.py
@@ -70,8 +70,8 @@ class OpenAITTSSettings(TTSSettings):
         speed: Voice speed control (0.25 to 4.0, default 1.0).
     """
 
-    instructions: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    speed: float | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    instructions: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    speed: float | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
 
 
 class OpenAITTSService(TTSService):
diff --git a/src/pipecat/services/settings.py b/src/pipecat/services/settings.py
index 62d6dfd50..b1f7539db 100644
--- a/src/pipecat/services/settings.py
+++ b/src/pipecat/services/settings.py
@@ -440,7 +440,7 @@ class TTSSettings(ServiceSettings):
             ``__init__`` methods do the same at construction time.
     """
 
-    voice: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    voice: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     language: Language | str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
 
     _aliases: ClassVar[dict[str, str]] = {"voice_id": "voice"}
diff --git a/src/pipecat/services/speechmatics/stt.py b/src/pipecat/services/speechmatics/stt.py
index 2597724bb..836a5668a 100644
--- a/src/pipecat/services/speechmatics/stt.py
+++ b/src/pipecat/services/speechmatics/stt.py
@@ -114,7 +114,7 @@ class SpeechmaticsSTTSettings(STTSettings):
         extra_params: Extra parameters for the STT engine.
     """
 
-    domain: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    domain: str | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     turn_detection_mode: TurnDetectionMode | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     speaker_active_format: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
     speaker_passive_format: str | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
@@ -125,18 +125,22 @@ class SpeechmaticsSTTSettings(STTSettings):
     additional_vocab: list[AdditionalVocabEntry] | _NotGiven = field(
         default_factory=lambda: NOT_GIVEN
     )
-    operating_point: OperatingPoint | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    max_delay: float | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    end_of_utterance_silence_trigger: float | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    end_of_utterance_max_delay: float | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    punctuation_overrides: dict[str, Any] | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    include_partials: bool | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    split_sentences: bool | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    enable_diarization: bool | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    speaker_sensitivity: float | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    max_speakers: int | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    prefer_current_speaker: bool | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
-    extra_params: dict[str, Any] | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    operating_point: OperatingPoint | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    max_delay: float | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    end_of_utterance_silence_trigger: float | None | _NotGiven = field(
+        default_factory=lambda: NOT_GIVEN
+    )
+    end_of_utterance_max_delay: float | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    punctuation_overrides: dict[str, Any] | None | _NotGiven = field(
+        default_factory=lambda: NOT_GIVEN
+    )
+    include_partials: bool | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    split_sentences: bool | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    enable_diarization: bool | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    speaker_sensitivity: float | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    max_speakers: int | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    prefer_current_speaker: bool | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
+    extra_params: dict[str, Any] | None | _NotGiven = field(default_factory=lambda: NOT_GIVEN)
 
     #: Fields that can be updated on a live connection via the Speechmatics
     #: diarization-config API — no reconnect needed.
diff --git a/src/pipecat/services/ultravox/llm.py b/src/pipecat/services/ultravox/llm.py
index c1cd8d750..967dc7886 100644
--- a/src/pipecat/services/ultravox/llm.py
+++ b/src/pipecat/services/ultravox/llm.py
@@ -67,7 +67,7 @@ class UltravoxRealtimeLLMSettings(LLMSettings):
         output_medium: The output medium for the model ("voice" or "text").
     """
 
-    output_medium: str | _NotGiven = field(default=NOT_GIVEN)
+    output_medium: str | None | _NotGiven = field(default=NOT_GIVEN)
 
 
 class AgentInputParams(BaseModel):