"Do I have an accent?" We all do, but it can be hard to judge what your accent sounds like to other people.
Do you think your accent is more subtle than other people's?
A study headed by Professor Holger Mitterer (2020) explored the question: Do second language learners perceive their own accents as closer to the target language compared to the accent of other learners?
Native speakers of German were recorded speaking English sentences. Weeks later, they returned in order to judge the accents of multiple voice recordings. What they didn't know was that their own voice recordings were amongst the ones they had to listen to, and their recordings were altered to sound like the opposite gender, effectively disguising their voice when it was played back to them!
We are not good at judging our own accents
The results showed that participants generally rated their own accents as better than other speakers, even when they couldn't recognize their own voice recording. This explains why you can still have persistent pronunciation errors even after years of speaking English. You don't even notice your speech differences! This shows that external feedback is essential to understanding and changing your speech.
Mitterer H, Eger NA, Reinisch E. My English sounds better than yours: Second-language learners perceive their own accent as better than that of their peers. PloS one. 2020;15(2):e0227643. doi:10.1371/journal.pone.0227643