I want to know if "easier than before" is correct in my sentence or not, and how I can say something makes things better than before. For example.
"Our smartphones make learning languages easier than before."
"Easier than before" gives the impression of an immediate improvement. There was a previous situation, and then you made a change, and now the situation is easier.
I got a non-stick frying pan, so cleaning up is easier than before.
The sentence implies a specific change or event. Cleanup is easier than before I got the pan.
By contrast, your example sentence is not "everyday English" but advertising lingo. In that lingo, they usually prefer to say "easier than ever before".
Our smartphones make learning languages easier than ever before!
Why do they do this? Because it makes their product the best yet, the latest in a chain of constant improvement... if it's easier than the previous product, it must also be the easiest ever. And why not use hyperbole to sell a product?
If a regular person says "easier than ever before", though, they'll sound like an ad. :)