Phrase generation approaches
I've found a survey on natural-language generation approaches by Albert Gatt, Emiel Krahmer, 2018. According to that, my question is about linguistic realization. And the paper mentions three most common ones:


human-crafted templates
human-crafted grammar-based systems
statistical approaches


If I remember correctly, there may also be rules-based NLG systems, which may be overlapping with the grammar-based in the above classification.

And I am sure there may be more approaches.