The voice said something that sounded like this: "Pigen laver mad på tvenstra" I thought that was very odd, but I wrote down what I heard and of course got it wrong. I even consulted google translate to see if maybe tv was actually pronounced as "tvenstra" in Danish and I had somehow missed that fact -- nope. I'm astonished no one else has reported this. I've listened to it many, many times and even asked my partner to do the same to make sure I'm not hallucinating. Has no one else heard this?
Yes, we say "et fjernsyn" and "et tv"
There are also some slang terms: et husalter (lit. a house altar), en flimmerkasse (lit. a flicker box), fjerneren (Such as: "Hvad kommer der i fjerneren i aften?")
There are no separate courses for speakers of certain English dialects. Most of the time the British alternative will be accepted where it has been reported or noticed. The more casual the expression or word, the less likely it will have been added. If you feel that your answer should be added then use the "Report a Problem" (this may be a flag icon next to the "correction" on the mobile apps) button and tick "My answer should be accepted". If you feel you need to explain using the free-write report then make sure you link it to your suggestion as these reports come in separately and both are done anonymously.
As for "yard" I assume you are referring to the translation used for "gård" in some contexts. Here "gård" does not mean "garden", it is more like a courtyard and I have been making this more obvious where I have seen it.