They show immense delight when they are able to detect their beginning sound in their environment. However I believe that knowing the alphabet from A to Z is a boring achievement and can lead to confusion as to what reading is. An over emphasis on letter names can make learning sounds and words difficult. A rigid version of the role of each letter should be avoided. Reading is not merely decoding symbols into words.
Meaning has to be obvious for the child to enjoy reading and be captivated by the process.
The understanding of words is helped if the child has been encouraged to enjoy creative play in as many situations as possible. Show the child that a book begins at the front and moves page by page to the back. Explain that the words are the marks on the white page and tell the child that the print goes from left to right and that we read the top line then the next and so on. Choose a book with a brief and easy text, one with repetitive phrases is excellent. Or you could write your own book using your child's own words.