We've all heard the advice: don't add salt when cooking lentils, because they'll toughen or not become soft or variations on that theme. For example, on lentils.org:

Be sure to season with salt after cooking – if salt is added before, the lentils will become tough.

The thing is, the same advice is given for basically all dried legumes, but Serious Eats debunked that - at least for cannellini beans. But lentils aren't much like beans, neither in size, cooked texture, nor even really in cooking processes. For example, soaking lentils in my experience just adds to the preparation time: it doesn't seem to make an appreciable difference in how long it takes to cook them, but it adds the time you had to take to soak them. So I'm not sure if the Serious Eats experiment really applies to lentils.

Has anyone either confirmed or debunked the don't-add-salt thing specifically for lentils?

We've all heard the advice: don't add salt when cooking lentils, because they'll toughen or not become soft or variations on that theme. For example, on lentils.org:

Be sure to season with salt after cooking – if salt is added before, the lentils will become tough.

The thing is, the same advice is given for basically all dried legumes, but Serious Eats debunked that - at least for beans (specifically, cannellini beans). But lentils aren't much like beans, neither in size, cooked texture, nor even really in cooking processes.¹ So I'm not sure if the Serious Eats experiment really applies to lentils.

Has anyone either confirmed or debunked the don't-add-salt thing specifically for lentils?

¹_{For example, soaking lentils in my experience just adds to the preparation time: it doesn't seem to make an appreciable difference in how long it takes to cook them, but it adds the time you had to take to soak them.}