The IsVowel(s) command tests whether every character in its argument s is an English language vowel.

The vowels are, by definition, the ten characters , , , , , , , ,  and . No other character is a vowel. In particular, the characters  and  are not considered to be vowels for this test.

If every character of the string s is a vowel character, then the value true is returned. Otherwise, the value false is returned. For the empty string, the tested condition is vacuously true.

The StringTools[IsVowel] command is thread-safe as of Maple 15.

For more information on thread safety, see index/threadsafe.