... and how to get all letters from a word

The function provided below returns the letters in a single word along with their position in the word:

CREATE OR REPLACE TYPE     TYP_WORD_LETTER AS OBJECT
(
  letter VARCHAR2(2),
  position  number(2)
)
/

CREATE OR REPLACE TYPE TYP_WORD_LETTER_COL
AS TABLE OF TYP_WORD_LETTER;
/

CREATE OR REPLACE FUNCTION get_word_letters (v_word VARCHAR2)
   RETURN typ_word_letter_col PIPELINED
AS
   ret_val   NUMBER;
   aletter   VARCHAR2 (2);
   pos       PLS_INTEGER  := 1;
BEGIN
   LOOP
      aletter := SUBSTR (v_word, pos, 1);
      PIPE ROW (NEW typ_word_letter (aletter, pos));
      pos := pos + 1;
      EXIT WHEN pos > LENGTH (v_word);
   END LOOP;

   RETURN;
END;
/