"Yo voy a un hotel."
Translation:I am going to a hotel.
Well, it was certainly an hotel when I went to school but it's a changing language so I'm prepared to accept somebody else's 'a' but Duolingo should also accept my 'an'. I want my heart back!
It is perfectly good English, IMHO, to use "an" before "h" when not aspirated. Whether the "h" is aspirated depends on where you come from, of course!
Some examples: A hotel, A hospital, A horse, A hacker, A hippie (the h is aspirated); An hour, An honest man, An hors d'oeuvre (the h is not aspirated); A/An herbal tea (that depends on how herbal is pronounced, either with the aspirated h or as "erbal".
I'm not sure whether there are regional varieties in which hotel is pronounced as "otel", in which case saying "an hotel" would make as much sense as saying "an herbal tea" when the h is not aspirated.
I teach ESOL (English for Speakers of Other Languages). The rule is "an" before vowel sounds and "a" before consonant sounds. As several posters have already pointed out, whether one uses "a" or "an" before a word starting with an h depends on the pronunciation of the h. Non-aspirated (silent) words use "an". Aspirated words (hard hs), use "a". I'm open to the idea that somewhere someone pronounces it 'otel; however, that would not be a correct pronunciation anywhere in the United States.