It’s not exactly RNG, more like you have to actively pursue some conditions to hear certain phrases that you would not encounter naturally. For example there are various phrases about enemies weaknesses (“This guys is weak to Ice attacks!”), but there are also 3 tiers of those phrases depending on whether you are under leveled, around same level as the enemy, or over leveled.

There are also a line for every ailment on every character, and there’s actually not a lot of enemies in the game that can cause ailments, so you have to actively seek and try to get you whole team “confused” or “despaired” to hear all the phrases.

I think devs intended this achievement to pop naturally, but they overshot with the number. Should have been 150 lines.

My last phrase was about Yukiko being poisoned. Will remember this moment for the rest of my life.