I sure would love to have some examples of grammar rules that have softened in your lifetime--and examples of applications. I'm trying to give my students a sense of the language being in flux--that what holds true today may be very different in the future. Perhaps 'grammar' is a bit too restrictive here because I'd like to cross into vocabulary applications as well.

Here's an example:

Splitting the infinitive was about as hard as splitting the atom when I was going through school. We simply weren't allowed to back in the 60s. Things changed--and now we can split the infinitive in even formal writing when the sentence flows more naturally by doing so. Example: I want to consciously observe when my little finger assumes incorrect position on the keyboard.

If you can even write a sentence that's a bit better than the one I used for splitting the infinitive, thanks.

Another rule I learned that's pretty much consistently broken these days--at least in the world of advertisement-- is the distinction between healthful and healthy.

Thanks for any input.