diff --git a/examples/sync_audio_streaming_with_predefined_voice_subtitles_print2stdout.py b/examples/sync_audio_streaming_with_predefined_voice_subtitles_print2stdout.py
index 7c7890d..4bb770a 100644
--- a/examples/sync_audio_streaming_with_predefined_voice_subtitles_print2stdout.py
+++ b/examples/sync_audio_streaming_with_predefined_voice_subtitles_print2stdout.py
@@ -24,7 +24,7 @@ VOICE = "zh-CN-YunjianNeural"
 
 def main() -> None:
     """Main function"""
-    communicate = edge_tts.Communicate(TEXT, VOICE, Boundary="SentenceBoundary")
+    communicate = edge_tts.Communicate(TEXT, VOICE, boundary="SentenceBoundary")
     submaker = edge_tts.SubMaker()
     stdout = sys.stdout
     audio_bytes = []
diff --git a/src/edge_tts/communicate.py b/src/edge_tts/communicate.py
index 52ea351..ff9bd63 100644
--- a/src/edge_tts/communicate.py
+++ b/src/edge_tts/communicate.py
@@ -19,14 +19,12 @@ from typing import (
     Literal,
     Optional,
     Tuple,
-    TypedDict,
     Union,
 )
 from xml.sax.saxutils import escape, unescape
 
 import aiohttp
 import certifi
-from typing_extensions import NotRequired, Unpack
 
 from .constants import DEFAULT_VOICE, SEC_MS_GEC_VERSION, WSS_HEADERS, WSS_URL
 from .data_classes import TTSConfig
@@ -311,19 +309,12 @@ def ssml_headers_plus_data(request_id: str, timestamp: str, ssml: str) -> str:
     )
 
 
-class CommunicateRequest(TypedDict):
-    """
-    A class to communicate with the service.
-    """
-
-    Boundary: NotRequired[Literal["WordBoundary", "SentenceBoundary"]]
-
-
 class Communicate:
     """
     Communicate with the service.
     """
 
+    # pylint: disable=too-many-arguments
     def __init__(
         self,
         text: str,
@@ -332,24 +323,13 @@ class Communicate:
         rate: str = "+0%",
         volume: str = "+0%",
         pitch: str = "+0Hz",
+        boundary: Literal["WordBoundary", "SentenceBoundary"] = "SentenceBoundary",
         connector: Optional[aiohttp.BaseConnector] = None,
         proxy: Optional[str] = None,
         connect_timeout: Optional[int] = 10,
         receive_timeout: Optional[int] = 60,
-        **kwargs: Unpack[CommunicateRequest],
     ):
-        """
-        Args:
-            boundary (str): The boundary to use for the TTS.
-                Defaults to "WordBoundary".
-                Valid values are "WordBoundary" and "SentenceBoundary".
-                If "WordBoundary", the TTS will return a word boundary for each word.
-                If "SentenceBoundary", the TTS will return a sentence boundary for each sentence.
-                    Which is more friendly to Chinese users.
-        """
-
         # Validate TTS settings and store the TTSConfig object.
-        boundary = kwargs.get("Boundary", "WordBoundary")
         self.tts_config = TTSConfig(voice, rate, volume, pitch, boundary)
 
         # Validate the text parameter.
diff --git a/src/edge_tts/data_classes.py b/src/edge_tts/data_classes.py
index dd5e60a..83da751 100644
--- a/src/edge_tts/data_classes.py
+++ b/src/edge_tts/data_classes.py
@@ -5,6 +5,7 @@
 import argparse
 import re
 from dataclasses import dataclass
+from typing import Literal
 
 
 @dataclass
@@ -17,7 +18,7 @@ class TTSConfig:
     rate: str
     volume: str
     pitch: str
-    boundary: str
+    boundary: Literal["WordBoundary", "SentenceBoundary"]
 
     @staticmethod
     def validate_string_param(param_name: str, param_value: str, pattern: str) -> str:
diff --git a/src/edge_tts/submaker.py b/src/edge_tts/submaker.py
index 71a3f22..490f663 100644
--- a/src/edge_tts/submaker.py
+++ b/src/edge_tts/submaker.py
@@ -1,7 +1,7 @@
 """SubMaker module is used to generate subtitles from WordBoundary and SentenceBoundary events."""
 
 from datetime import timedelta
-from typing import List
+from typing import List, Optional
 
 from .srt_composer import Subtitle, compose
 from .typing import TTSChunk
@@ -14,6 +14,7 @@ class SubMaker:
 
     def __init__(self) -> None:
         self.cues: List[Subtitle] = []
+        self.type: Optional[str] = None
 
     def feed(self, msg: TTSChunk) -> None:
         """
@@ -26,7 +27,16 @@ class SubMaker:
             None
         """
         if msg["type"] not in ("WordBoundary", "SentenceBoundary"):
-            raise ValueError("Invalid message type, expected 'WordBoundary'")
+            raise ValueError(
+                "Invalid message type, expected 'WordBoundary' or 'SentenceBoundary'."
+            )
+
+        if self.type is None:
+            self.type = msg["type"]
+        elif self.type != msg["type"]:
+            raise ValueError(
+                f"Expected message type '{self.type}', but got '{msg['type']}'."
+            )
 
         self.cues.append(
             Subtitle(
@@ -37,38 +47,6 @@ class SubMaker:
             )
         )
 
-    def merge_cues(self, words: int) -> None:
-        """
-        Merge cues to reduce the number of cues.
-
-        Args:
-            words (int): The number of words to merge.
-
-        Returns:
-            None
-        """
-        if words <= 0:
-            raise ValueError("Invalid number of words to merge, expected > 0")
-
-        if len(self.cues) == 0:
-            return
-
-        new_cues: List[Subtitle] = []
-        current_cue: Subtitle = self.cues[0]
-        for cue in self.cues[1:]:
-            if len(current_cue.content.split()) < words:
-                current_cue = Subtitle(
-                    index=current_cue.index,
-                    start=current_cue.start,
-                    end=cue.end,
-                    content=f"{current_cue.content} {cue.content}",
-                )
-            else:
-                new_cues.append(current_cue)
-                current_cue = cue
-        new_cues.append(current_cue)
-        self.cues = new_cues
-
     def get_srt(self) -> str:
         """
         Get the SRT formatted subtitles from the SubMaker object.
diff --git a/src/edge_tts/util.py b/src/edge_tts/util.py
index d6fe3eb..0d551ac 100644
--- a/src/edge_tts/util.py
+++ b/src/edge_tts/util.py
@@ -75,9 +75,6 @@ async def _run_tts(args: UtilArgs) -> None:
             elif chunk["type"] in ("WordBoundary", "SentenceBoundary"):
                 submaker.feed(chunk)
 
-        if args.words_in_cue > 0:
-            submaker.merge_cues(args.words_in_cue)
-
         if sub_file is not None:
             sub_file.write(submaker.get_srt())
     finally: