Stuttering on words I cant improvise?

Stuttering on words I cant improvise? i have no idea if this is common or not but I mostly stutter on words that I can't improvise. which is why I stutter with pronouncing names. if there is a word that I can replace with or if i can rephrase something, my stuttering becomes a lot better. have any of yall experienced this? if so, how can I get better with words I cant improvise on?