If you are used to knit in the round, you will be able to make your own sorting hat. I just give you the bases because I did not take any notes of the making, except for last part, and I totally improvised the hat. The number of stitches and rows will depend from your choice of yarn, obviously, and from the size you want for it. This hat was designed for adults (but also works on children that like). It doesn't need to be felted, the good news is that you can take any yarn you have (that I did).

It has a pocket inside and the mouth is opened: it can speak if you put papers in the mouth. Also, you may put a Arduino device in the inside pocket to make it really speak (if you know how to do, that I can't do, unfortunately).

Step 1: You Will Need

a set of dpns a circular needle (optional)
yarn that must be knitted with bigger needles than the one you choose to knit very tightly
a scrap of contrasting yarn to mark the mouth
stitch markers
safety pins or stitch holder
tapestry needle for the finishing
stuffing

Optional: a brown colour pencil or a brown make-up pencil for the eyes.

You also need something to note what you did and the last part of the hat to make the same for the bottom of the brim and the inside pockets.

Step 2: The Hat

Cast on 3 stitches and join in round.

I knitted it with 4 dpns then a circular. I began with 3 stitches, 1 row, an increase in every stitch of the row, 1 or more row (can’t remember), again an increase in every stitch of the row then, the increases are on the first and on the middle stitch of every needle and when I wanted or thought to make them (exactly like that).

I represented the eyes first with safety pins to have an idea of the height, then the first lip also with safety pins. I made 2 rows with contrasting yarn on the the 15-20 middle stitches because I wanted an open mouth. Then for the other lip, I too used safety pins or a needle holder. At this point I counted a bit more to have a good length and circumference (it is for an adult head). Do not forget to note it.

Do not forget to write notes on the last part of the sorting hat if you want to knit a “lining” to make it more rigid.

Step 3: The Brim and the Mouth

Begin with two rows in garter stitch. Then make an increase every 12 stitches, one row.

Make these increases: they should be one over this other every two rows (second series of increase will be 13 stitches, an increase, etc.). Finish the top of the brim with two rows in garter stitch. Then make the same work making decreases instead of increases. I did it in black, but feel free to use any colour you want (or you have on hand). End the “lining” with some rows in rib.

The mouth: remove the contrasting yarn, pick up the stitches and knit some rows in the round. Cast off.

Step 4:

Sew the border of the mouth in the inside. Make the eyes by sewing sorts of rolls.

Sew the “lining” to the hat with three vertical seams that will make useful pockets.

Stuff the top, stop it by sewing a piece of fabrics or of knitting (I take an old sweater). If you want, sew another piece on the hat with apparent stitches.

Congratulations, it is done!

I hope you have fun in making this hat.