I briefly stuttered as a kid—what was that

I briefly stuttered as a kid—what was that When I was in grade four, I noticed that I occasionally stuttered while trying to say the "o" sound — like when I tried to say "onion," I sometimes couldn't get the word out and would just stay silent since the kids laughed at me. It happened only a few times, mostly while talking with friends. But within a year, the issue disappeared completely, and I never stuttered again. Now, as an adult, I wonder what really caused it :)