diff --git a/TTS/tts/utils/text/cleaners.py b/TTS/tts/utils/text/cleaners.py
index f829e4cc..fc87025f 100644
--- a/TTS/tts/utils/text/cleaners.py
+++ b/TTS/tts/utils/text/cleaners.py
@@ -18,34 +18,37 @@ from .french.abbreviations import abbreviations_fr
 _whitespace_re = re.compile(r"\s+")
 
 
-def expand_abbreviations(text, lang="en"):
+def expand_abbreviations(text: str, lang: str = "en") -> str:
     if lang == "en":
         _abbreviations = abbreviations_en
     elif lang == "fr":
         _abbreviations = abbreviations_fr
+    else:
+        msg = f"Language {lang} not supported in expand_abbreviations"
+        raise ValueError(msg)
     for regex, replacement in _abbreviations:
         text = re.sub(regex, replacement, text)
     return text
 
 
-def lowercase(text):
+def lowercase(text: str) -> str:
     return text.lower()
 
 
-def collapse_whitespace(text):
+def collapse_whitespace(text: str) -> str:
     return re.sub(_whitespace_re, " ", text).strip()
 
 
-def convert_to_ascii(text):
+def convert_to_ascii(text: str) -> str:
     return anyascii(text)
 
 
-def remove_aux_symbols(text):
+def remove_aux_symbols(text: str) -> str:
     text = re.sub(r"[\<\>\(\)\[\]\"]+", "", text)
     return text
 
 
-def replace_symbols(text, lang: Optional[str] = "en"):
+def replace_symbols(text: str, lang: Optional[str] = "en") -> str:
     """Replace symbols based on the language tag.
 
     Args:
@@ -78,14 +81,14 @@ def replace_symbols(text, lang: Optional[str] = "en"):
     return text
 
 
-def basic_cleaners(text):
+def basic_cleaners(text: str) -> str:
     """Basic pipeline that lowercases and collapses whitespace without transliteration."""
     text = lowercase(text)
     text = collapse_whitespace(text)
     return text
 
 
-def transliteration_cleaners(text):
+def transliteration_cleaners(text: str) -> str:
     """Pipeline for non-English text that transliterates to ASCII."""
     # text = convert_to_ascii(text)
     text = lowercase(text)
@@ -93,7 +96,7 @@ def transliteration_cleaners(text):
     return text
 
 
-def basic_german_cleaners(text):
+def basic_german_cleaners(text: str) -> str:
     """Pipeline for German text"""
     text = lowercase(text)
     text = collapse_whitespace(text)
@@ -101,7 +104,7 @@ def basic_german_cleaners(text):
 
 
 # TODO: elaborate it
-def basic_turkish_cleaners(text):
+def basic_turkish_cleaners(text: str) -> str:
     """Pipeline for Turkish text"""
     text = text.replace("I", "ı")
     text = lowercase(text)
@@ -109,7 +112,7 @@ def basic_turkish_cleaners(text):
     return text
 
 
-def english_cleaners(text):
+def english_cleaners(text: str) -> str:
     """Pipeline for English text, including number and abbreviation expansion."""
     # text = convert_to_ascii(text)
     text = lowercase(text)
@@ -122,7 +125,7 @@ def english_cleaners(text):
     return text
 
 
-def phoneme_cleaners(text):
+def phoneme_cleaners(text: str) -> str:
     """Pipeline for phonemes mode, including number and abbreviation expansion.
 
     NB: This cleaner converts numbers into English words, for other languages
@@ -136,7 +139,7 @@ def phoneme_cleaners(text):
     return text
 
 
-def multilingual_phoneme_cleaners(text):
+def multilingual_phoneme_cleaners(text: str) -> str:
     """Pipeline for phonemes mode, including number and abbreviation expansion."""
     text = replace_symbols(text, lang=None)
     text = remove_aux_symbols(text)
@@ -144,7 +147,7 @@ def multilingual_phoneme_cleaners(text):
     return text
 
 
-def french_cleaners(text):
+def french_cleaners(text: str) -> str:
     """Pipeline for French text. There is no need to expand numbers, phonemizer already does that"""
     text = expand_abbreviations(text, lang="fr")
     text = lowercase(text)
@@ -154,7 +157,7 @@ def french_cleaners(text):
     return text
 
 
-def portuguese_cleaners(text):
+def portuguese_cleaners(text: str) -> str:
     """Basic pipeline for Portuguese text. There is no need to expand abbreviation and
     numbers, phonemizer already does that"""
     text = lowercase(text)
@@ -170,7 +173,7 @@ def chinese_mandarin_cleaners(text: str) -> str:
     return text
 
 
-def multilingual_cleaners(text):
+def multilingual_cleaners(text: str) -> str:
     """Pipeline for multilingual text"""
     text = lowercase(text)
     text = replace_symbols(text, lang=None)
@@ -179,7 +182,7 @@ def multilingual_cleaners(text):
     return text
 
 
-def no_cleaners(text):
+def no_cleaners(text: str) -> str:
     # remove newline characters
     text = text.replace("\n", "")
     return text