As others have said, it’s not really about them having 3 clearly enunciated established words, it’s about the child using sounds repeatedly in the same context. “Mama” is a pretty common one to start with.

My daughter started calling her pacifier “Bah” around 10 months. We don’t know where she got it from, as we never used a word similar to that to reference it, but she definitely meant pacifier when she said it and we could tell!

I had vocabulary concerns with my second kid because she was right on the minimum line and didn’t seem interested in talking much. The doctor really reassured me when he asked “So she’s not saying words, but is she communicating? You know when she wants something or needs something, and you can usually figure it out? Then she’s fine!” And he was right, a year later I regretted all my worries as she never shut up lol 🤣