Stutter at work

Stutter at work So I work in an Amazon warehouse. I just started working here about 3 days ago and so far it's been okay. I don't really talk to anyone , but some people have introduced themselves to me. I've had difficulty talking to some co workers because I stutter and block sometimes. Today I was sent to an area i'd never been and my manager asked me where I was working yesterday. I wanted to say "inbound" because that is what it's called but I wasn't able to. After struggling with that word he finally said oohhh inbound. He looked at me like I was mentally challenged and walked away. How do you guys deal with situations like these?