Count vowels and consonants in an array

I am trying to write a function which will return number of vowels and consonants. Using the IF statement function will successfully compile, however when I call it in the select it shows the message :

"Conversion failed when converting the varchar value 'MAMAMIA' to data type int."`

I tried with the CASE statement, but there are too many syntax errors and i think it is not the best method of solving the problem using CASE ...

 CREATE FUNCTION VOW_CONS(@ARRAY VARCHAR(20))
 RETURNS INT
 BEGIN

 DECLARE @COUNTT INT;
 DECLARE @COUNTT1 INT; 
 
 SET @COUNTT=0;
 SET @COUNTT1=0;

 WHILE (@ARRAY!=0)
 BEGIN
  IF(@ARRAY LIKE '[aeiouAEIOU]%') 
 
 SET @COUNTT=@COUNTT+1 

 ELSE SET @COUNTT1=@COUNTT1+1

/*
 DECLARE @C INT; 
SET @C=(CASE @SIR WHEN 'A' THEN  @COUNTT=@COUNTT+1; 
        WHEN 'E' THEN  @COUNTT=@COUNTT+1
        WHEN 'I' THEN  @COUNTT=@COUNTT+1
        WHEN 'O' THEN  @COUNTT=@COUNTT+1 
        WHEN 'U' THEN  @COUNTT=@COUNTT+1 
        WHEN 'A' THEN  @COUNTT=@COUNTT+1
        WHEN ' ' THEN ' '
   ELSE  @COUNTT1=@COUNTT1+1
   END) 
*/

 END

  RETURN @COUNTT;

END

SELECT DBO.VOW_CONS('MAMAMIA')