I need to know where to begin to teach an illiterate adult.

Teaching them what? How are their learning funtions besides not being able to read ?

Start with teaching the alphabet song, then have the student point to the letters as he sings them. Once the letters are learned, teach the sound that each one makes. Next, teach the consonant digraphs (two letters that make one sound, such as 'th' - it doesn't say 't' 'h', but 'th'), then vowel digraphs ('ai' makes the long a sound). In addition, work on the Dolch words (high frequency words) and sight words (words that are not pronounced as they are spelled). Good Luck

Start with teaching the alphabet song, then have the student point to the letters as he sings them. Once the letters are learned, teach the sound that each one makes. Next, teach the consonant digraphs (two letters that make one sound, such as 'th' - it doesn't say 't' 'h', but 'th'), then vowel digraphs ('ai' makes the long a sound). In addition, work on the Dolch words (high frequency words) and sight words (words that are not pronounced as they are spelled). Good Luck

Also, using pictures helps the person better understand the sounds. Toy stores and school supply stores have an ample selection of picture books with simple, colorful illustrations.