At their worst: they become a slippery slope of insecurity and codependence;
What Your Love Language Says About You
Kris Gage

From my experience, these aren’t fixed in stone. People change over time. The “languages” they speak are more attributed to their current mindset and worldview, which changes as people change.

I also think most people don’t fall neatly into just one or two categories. That said, it can be instructive when deciding how to show appreciation in the moment if you have at least a cursory understanding of the person in question.