> I am knitting a sweater. My pattern says mark center st. Shape neck
> continuing to work armhole decs, work to center st. join another hank of
> yarn and bind off center st. work to end. Working both sides at once
> separate hanks of yarn continue to work armhole decs and at same time dec
> st at each neck edge every ts row 21 times. What does all this mean in
> plain English?
You’ll need another end of yarn because you work both shoulders separately. Continue with the shaping at the armhole edges, knit to the center st, drop that yarn, pick up the other yarn end and bind off 1 st, then finish the row with the new yarn, decreasing at the end. Turn and work to the bound off stitch, drop the yarn, pick up the other and work to the end of the row. Turn, do the armhole dec, work to 2 sts before the split, k2tog, drop the yarn, pick up the other, ssk and work to the end, decreasing at the end of the row. Work back on the WS row, and continue making decs at both the beg and end and at the center neck edges.
Here is some help with the abbreviations:
st - stitch
rs - right side
decs - decrease
Like you, I found several knitting patterns difficult to decipher because of all the abbreviations and lack of complete glossaries. I ended up buying a book titled “Vogue Knitting - The Ultimate Knitting Book”, and it has helped immensely.
As a note on binding off:
Binding off links stitches which are no longer to be worked and keeps them from unraveling. The resulting selvage can be connected to other pieces of knitting or it can stand on its own. The bound-off edge should be elastic, but firm - not too loose or too tight. Knitters often tend to bind off too tightly. A way to reduce this tendency is to use a large needle to bind off. Unless otherwise stated, you should bind off in the stitch pattern used for the piece.