Is there a smaller tautogram checker? I got into code-golfing recently and tried to write the smallest tautogram checker.
A tautogram is a sentence in which all words start with the same letter, for example: Flowers flourish from France.
Given a sentence as input, determine whether it is a tautogram.
Test Cases
Flowers flourish from France
    True

This is not a Tautogram
    False

I came up with this python code (because it is my main language):
print(True if len(list(set([x.upper()[0] for x in __import__('sys').argv[1:]]))) == 1 else False)

Usage:
python3 tautogram.py Flowers flourish from France
# True
python3 tautogram.py This is not a Tautogram
# False

The sentence may contain commas and periods, but no other special characters, only upper and lower case letters and spaces.
Its size is 98 bytes. Is there a smaller solution in any language?
05AB1E, 5 bytes

l#€нË


Try it online!



l      # Lowercase input.
 #     # Split on spaces.
  €н   # a[0] of each.
    Ë  # All equal?


Did this on mobile excuse the no explanation.