- LetterQ[string] by default gives False if string contains any space or punctuation characters.
- LetterQ handles both ordinary and special characters.
- LetterQ treats as letters all special characters explicitly listed as letters in the table in "Named Characters".
- In general, LetterQ treats as letters all characters that appear as ordinary text in any language.
- LetterQ treats as letters such special characters as α, , ℒ, and æ.
- LetterQ does not treat as letters ∅ (\[EmptySet]), ℏ (\[HBar]), Å (\[Angstrom]), or ∑ (\[Sum]).
Introduced in 1991Updated in 1996