What Titus said.
The guy teaching doesn't know you, so here are his options:
1. Assume no-one knows the technical terms and explain everything:
- the new players who would have been too timid to ask are super happy.
- the new players who would otherwise have asked are happy.
- the people who know the terms are bored.
- the people who know the terms and are grumpy think this is condescending and leave.
- the class covers 50% less stuff.
2. Assume the class knows the common terms and will ask about anything else:
- timid new players are frustrated.
- non-timid new players ask questions.
- everybody else has a good time
- the class delivers more content
Between that and habit, most teachers will assume you know the common terms. In all the classes I've been in, both as a student and as a teacher (*), the number of classes where a student was discouraged to ask a teacher for that sort of clarification was, surprisingly enough,
(*) I haven't kept track, and both these numbers have probably, and mercifully for my sanity, been long lost, but I'm pretty sure it's a 3-digit number.