This is always what I understood, you have words for letters but you only really use them when you need to spell something out otherwise you use other words. I

This is always what I understood, you have words for letters but you only really use them when you need to spell something out otherwise you use other words. I have never learned any sign language but I assumed it worked in the same way, or else there would be no advantage to signing over writing what you want to say down.