Aligned translations are created using our own software app called Bilara.
All Bilara translations must be free from any copyright (i.e. CC0 or public domain.) The majority of non-aligned texts have some kind of copyright, therefore they cannot even be retroactively added to the Bilara system.
There is no way on SuttaCentral itself to show line by line with the Pali on non-aligned texts. That’s the whole reason there are aligned texts.
However, you can use the SC browser extension to display the Pali along side the translation without it being aligned:
They scroll independently, so you have to do the aligning yourself.
This is the setting in the extension:
