In the past, in fiction or what have you, every time someone has a seizure, they always try and prevent the person from swallowing his/her tongue.
Unfortunately, this is fiction-doing so only gets you bitten-pretty badly. What gives?
In some seizures, the person’s tongue may fall back, obstructing their airway. If obstructed for very long, the brain damage or death can occur. Turning the person to the side often relieves the obstruction, but for many years, using a bite block was the accepted way of keeping the airway open.
It is possible to choke during some types of seizures (a tonic-clonic grand mal, e.g.), on either soft tissues or secretions or vomit. More precisely, it’s possible to make choking sounds; actually choking to death is rare, and even serious aspiration is not all that common, depending on the cause and circumstances of the seizure.
Somewhere someone got the idea the seizing patient was “swallowing their tongue” and the phrase caught on.
On average it’s a better strategy to provide some very simple positioning strategies, try to make sure the individual isn’t hurting themselves, and not stick anything at all into their mouth. You are right that a seizing patient will not swallow their tongue or any other soft tissue if their underlying anatomy is normal.