At first glance, there may not be a lot of obvious differences between a crochet pattern written in British English and one written in American English. After all, both patterns use yarn and a crochet hook; they may even have stitches that sound the same. However, a stitch in American English is not necessarily the same as the stitch of the same name in British English. To use a pattern written in British English, some translation is required.
Some stitches are the same in both versions of crochet. The chain stitch, which involves making one yarn over and drawing up one loop, is the same in both versions. Also is the slip stitch, which involves inserting the hook into a stitch and drawing up a loop through all of the loops on the hook.
Single vs. Double
In American English, a single crochet stitch is made by inserting a hook into a stitch, pulling the yarn over the hook, pulling the hook back through the stitch and making one more yarn over before drawing that loop through all of the loops on the hook. In British English, this is the double crochet stitch.
Double vs. Treble
In American crochet, to make a double crochet you complete the following steps: yarn over, insert the hook into the next stitch, yarn over and draw up a loop, yarn over and draw through two loops on the hook, yarn over and draw through the remaining loops. In British English, this stitch is called a treble crochet.
The half double crochet stitch in American crochet is made in this manner: yarn over and insert the hook into the next stitch. Yarn over and pull up a loop, then yarn over and draw through all of the loops on the hook. In British terminology, this stitch is a half treble crochet.
Triples, Trebles and Double Trebles
In American crochet, a triple crochet stitch, also known as a treble crochet stitch, is made this way: yarn over twice, insert the hook into the next stitch, yarn over and draw up a loop, yarn over and pull through two loops on hook, yarn over and pull through two more loops, yarn over and pull through remaining loops. In British terminology, this is a double treble crochet stitch.
When an American crocheter finishes a piece, she binds off or fastens off her work; a British crocheter casts off. An American crocheter measures her gauge to see if her stitches fit in a certain size; a British crocheter measures her tension instead.