an is used before vowel sound and a is used before consonant sound. Human is a consonant sound so it is a human.

I think in written English the correct version is "an human". Although nobody ever speaks that "n". This was definitely the rule I learned at school. However, rules do change, so I suggest asking a properly trained ESL teacher on this one.

human starts with sound h so it is consonant. university starts like (youniversity).notice the subtle difference.so, it is consonant.hour, though it starts with h but in pronunciation h is hidden.the pronunciation hour is like (our), beginning with vowel sound.umbrella starts like (ambrella) beginning with vowel sound.hope find your ans.

(consonant sound) a human. a university (vowel sound) an hour an umbrella can you see the diference? See you. Gio. [If I have errors, please let me know]