Do you want a dialog system that doesn't rely on dialog trees? Do you want dynamic dialog in your unity games? Try the Ask/Tell Dynamic Dialog asset on the unity asset store. It uses a simple ask/tell input system based off of older point and click games and dynamic  responses based on the Left4Dead bark system. This uses a series of conditions to create a fuzzy pattern matching state machine to handle the replies for your NPCs. Check it out now:
https://assetstore.unity.com/packages/tools/input-management/ask-tell-dynamic-di...