Mi portas pluvombrelon, ĉar pluvas. = I am carrying an umbrella because it is raining.
Mi portas pluvombrelon, tial pluvas. = I am carrying an umbrella; that's why it is raining. (= ... and because of that, it is raining)
Ambaŭ donas kialon, sed en la unua frazo, la pluvado estas la kialo por la portado de pluvombrelo, sed en la dua, la portado estas kialo por la pluvado.
What is the difference to saying "why is the mirror not in the bathroom?"
That would imply that there is a mirror somewhere. Whereas the original sentence doesn't imply it. There could be no mirror in the house at all and someone may still ask the original question whereas yours would be grammatically incorrect due to the presence of the mirror, or rather the lack thereof.
"Kial la spegulo ne estas en la banĉambro?"
Big difference: "la spegulo" (since you used definite "the mirror"). Second difference, the word order.
why is "Why there is no mirror in the bathroom" not good. For me it is exactly the same as "why is there no mirror in the bathroom"! Don't see the difference...
Word order: one starts "why there is..." and the other starts "why is there...".
As a normal question in English, it has to be "Why is there ...?".
The other word order would be used in an indirect question, such as in "I don't know why there is ...."
You can't use one word order in the other situation.
I'm guessing from your name that you're Dutch? Isn't it similar there? "Waarom is er een spiegel in de badkamer?" maar "Ik weet niet, waarom er geen spiegel in de badkamer is" with different word order.
Thanks! And yes, I am Dutch. My English is good enough to follow the lessons, but sometimes I am tested for my knowledge of the English language, not my understanding of Esperanto. And I think that shouldn't be! If I wanted that, I would follow lessons English...
Look at the bright side: You are learning one language and fine tuning another!
When you mistake spegulo for silverware for some reason and the person voicing their outrage seems a bit mad :D
I don't know how it sounded six months ago, probably the audio was updated, but now I can clearly hear "kial ne".
A necesejo is a room with a toilet. It's a room for "performing the necessities" - defecating and urinating.
A banĉambro is a room with a bathtub, a shower, or at least a sink. It's a room for washing.
Some rooms have both, but not all, so if you want to empty your bladder and ask for the banĉambro, you may end up in a room with a bathtub and a sink but no toilet; and conversely, behind a door marked necesejo you may not find a shower.