What intrigued me here, was the form "venha" as opposed to "vem". If the sentence is negated, we have to use present subjunctive, not the 'normal' imperative form. (cf. http://en.wikipedia.org/wiki/Portuguese_verb_conjugation#Imperative)
Here you can see how to conjugate the imperative form with "tu" and "vós".
About the most natural form, I agree with you. At least in São Paulo (BR), we use the third person singular in simple present and this way is equal to the second person in imperative. So, in informal language, we say "vem aqui", not "venha aqui". But we never use the form of "vós".
Thanks for the link, as in Duolingo "Words" section all imperative forms are "venha" for all persons, even for "eu" and "nós" :) https://www.duolingo.com/dictionary/Portuguese/venha-vir-verb-imperative-third+person-singular/99b12bc88bb9c03e39b618d3c0d6f774
Probably no chance to report it.
If the accent is on "i" in "aqui", then why isn't it shown? "Aquí" would be more logical in my opinion.
The accent rules were made for putting accents in the fewest number of words. That is the logic.
When the last syllable is stressed, it will have an accent if the word ends in -a, -e, -o, -em, or -ens: Canadá, buquê, robô, refém, parabéns. If the word ends in -i, -u, -z, -r, -l and other endings, it needs no accent: abacaxi, urubu, rapaz, computador, quintal. Words like país (pa-ís) and baú (ba-ú) have accents, because the letters -i and -u are preceded by other vowels, but they are in different syllables.
Yes, thanks for the explanation, but isn't "aqui" pronounced as ah-KEY, and not as AH-key?