Was it the letter L? This is the last one for mine to learn. I briefly drew attention to working on it the past few days, but not too much to take away from her communication, and she is finally getting it. She first got it as the middle sound and now is starting to get the beginning sound.
I had a cousin I called Wara when I was a kid bc I couldn't say Lara when I was young. I was also wondering if it was genetic and if anyone else did anything to help LO along.