diff --git a/manimlib/mobject/svg/labelled_string.py b/manimlib/mobject/svg/labelled_string.py
index 1cd2b2a1..3f45c38a 100644
--- a/manimlib/mobject/svg/labelled_string.py
+++ b/manimlib/mobject/svg/labelled_string.py
@@ -373,6 +373,8 @@ class LabelledString(_StringSVG, ABC):
         return []
 
     def check_overlapping(self) -> None:
+        if len(self.label_span_list) >= 16777216:
+            raise ValueError("Cannot label that many substrings")
         for span_0, span_1 in it.product(self.label_span_list, repeat=2):
             if not span_0[0] < span_1[0] < span_0[1] < span_1[1]:
                 continue
diff --git a/manimlib/mobject/svg/mtex_mobject.py b/manimlib/mobject/svg/mtex_mobject.py
index a219cc19..70128b1f 100644
--- a/manimlib/mobject/svg/mtex_mobject.py
+++ b/manimlib/mobject/svg/mtex_mobject.py
@@ -266,11 +266,12 @@ class MTex(LabelledString):
         result = self.get_replaced_substr(self.full_span, span_repl_dict)
 
         if self.tex_environment:
-            result = "\n".join([
-                f"\\begin{{{self.tex_environment}}}",
-                result,
-                f"\\end{{{self.tex_environment}}}"
-            ])
+            if isinstance(self.tex_environment, str):
+                prefix = f"\\begin{{{self.tex_environment}}}"
+                suffix = f"\\end{{{self.tex_environment}}}"
+            else:
+                prefix, suffix = self.tex_environment
+            result = "\n".join([prefix, result, suffix])
         if self.alignment:
             result = "\n".join([self.alignment, result])
         if use_plain_file: