A "cackle" was the mating call of the hen!!! Now I'm showing my age here and I kind of hinted at this in the gobble thread but that's what we all thought. Our yelps were also limited to 4 syllable's. lol We'd sit at the base of a tree and every 30 min. or so we'd let out a loud cackle or a series of 4 yelps and once in a while we'd gobble with our box calls.
I still use a cackle once in a while on approaching gobblers that I'm trying to keep tabs on. I usually consider silence as a good thing because it's like they're on their final approach but once in a while if they're taking too long to cover those last 100 yds or so i'll just cackle. They will gobble!! I'm not worried about movement because I'm a mouthcall guy and lot's of times I've been able to make adjustments because they've circled and they're off to one side or the other or behind me. If you do this long enough you'll find that turkeys have an uncanny ability to get by you and once in a while a good ol cackle will save you. I picked up this trick on an old 8 track tape from Quaker Boy. The late great Dick Kirby said that he had never cackled at an approaching gobbler and not gotten a response. Just a little tidbit to think about.
Man, turkey calling and hunting has changed a lot.