"The radio is on the table."
Translation:Tá an raidió ar an mbord.
If you mean specifically in the ar an X case, there’s no distinction in meaning; Ulster Irish tends to use the lenited form, and the other dialects tend to use the eclipsed form.
yeh that's what i meant. The suggested answers for this were both "ar an mbord" and "ar an bhord" which felt surprising.
My understanding is that tabla is used in Ulster Irish and bord is used everywhere else, so I'm surprised it lists both the lenited and eclipsed versions as correct.