Yup - we train ourselves to ignore distinctions as “not meaningful” because of our native languages, and then when we learn another language, one that uses those distinctions, it bites us back. You can get it later on, mind you, but it’s always a bit of a pain.

Yep, this is exactly what I've been doing through. I need to find an instance in English where a word uses the 싸 sound (ssa) but I still haven't found any yet!