Rolling/trilling it (Spanish, Russian) or replacing with L (Japanese, Korean).
Especially tricky for speakers of: Japanese, Korean, Mandarin, Spanish, French, German.
These two words differ by exactly one sound. Tap both — can you hear it?
Record yourself saying red, then compare with the target. Your audio stays on this device — nothing is uploaded.
Tap the speaker to hear each word; tap the word for its full pronunciation page.