An Alternative Pig Latin Converter

pig-parser.xqy

xquery version "3.0";

declare function local:pig-parser($word as xs:string?) as xs:string?
{
  let $vowels := ("a","e","i","o","u","y")
  let $first-letter := fn:lower-case(fn:substring($word,1,1))
  return 
    if ($first-letter = $vowels) then $word || "ay"
    else local:pig-parser(fn:substring($word,2) || $first-letter) 
};

string-join(
    let $sentence := "I speak Pig Latin"
    for $word in fn:tokenize($sentence, " ")
    let $word := local:pig-parser($word)
    return $word, " ")