it says 'halad' also means 'go,' so why can't it be translated as "the girl goes" ?
I believe that's better translated as "a lány megy". To proceed is a lot more accurate translation for halad, especially as it doesn't only mean proceeding by movement, but also, for example, proceeding with a project. But since go is one of the hints, maybe you should try reporting, and maybe they'll add it.
Isn't there something like "Did you hear?" which sounds really similar to "halad" in Hungarian?
"Did you hear?" would be "hallottad?". I think it must be really difficult for non-Hungarians to hear the difference between "a" and "o". It is similar to that when Hungarians do not hear or do not listen to the difference between "pan" and "pen".
You might mean "Hallod?" ="Do you hear (it)?". But the pronunciation is not that similar.
Are most Hungarian verbs like this? Like having a meaning that consists of multiple words in English
Blame English for not having words for certain things :D Anyway, in English we use compound structures for some tenses with auxiliary verbs etc. while Hungarian solves these problems in different ways. E.g. "I will have been waiting for you" (really a monster for foreign speakers!) would go simply "Megvártalak volna" in Hungarian, but the difference is the structure and the general approach to tenses in the two languages.
On the other hand, I've read somewhere that daily used English has the smallest vocabulary among the European languages while Hungarian has one of the largest. But take it as a rumour only, I don't remember the source :D
Never rely on Google Translate, especially don't if you try to cope with Hungarian. GT sometimes translates completely gibberish, other times it suggests just the contrary of the statement, etc. "Girl is walking" means "A lány sétál" or "A lány gyalogol".
Actually "A lány halad" is a very unfortunate example as it has very different meanings in different contexts. It is either express a progress or an advancement, a forward moving (by any means, as it has the focus on the moving itself) or getting ahead. "A fiúnak túl nehéz a magyar, de a lány halad" would mean "Hungarian is too difficult for the boy but the girl is getting ahead". You may get this easier if you remember that "halad" is a smooth movement ahead or forward and it can mean either spatial movement or getting ahead with something. "What about doing the dishes?" "I don't care but the girl does it well" – "Hogy állsz a mosogatással?" "Nem foglalkozom vele, de a lány halad [vele]" etc...
I grew up hearing my parents talking Hungarian and never heard that word and others. They used to say megyunk walkolni instead of setalni :)
Please note that is non-standard, but a kinda mixed talk we call Hunglish ;)