Translation:The bus is standing beside the house, in which nobody lives.
No, amellett doesn't belong there, instead you need "amelyik mellett" for the relative clause.
"A mellett" is the demonstrative pronoun az together with mellett to mean "next to that (object)". And in the relative clause you have a relative pronoun, amelyik, coupled with mellett, so "next to which".
Amellett is a different word. It's an adverb that's used without referring to any concrete object. It means "besides" or "additionally", as in:
- Amellett meg szeretném említeni, hogy az óvónők nem repülnek. - Besides that, I want to mention that kindergarten teachers do not fly.
In general, if a postposition is placed behind a noun or pronoun, like in "a mellett", it refers to a concrete object. But if you write it as one word, amellett, it becomes an adverb that doesn't refer to anything particular within the sentence. Instead, it most often puts the entire sentence in a relative position to its context. (Like when you make some statement, and then add another one by starting with "Besides" or "In addition". You put the new statement next to the other.)
There are a couple of these pairs:
- a mellett, e mellett - next to that/this; amellett, emellett - in addition to that/this, besides
- az előtt, ez előtt - before that/this, in front of that/this; azelőtt, ezelőtt - before that/this point, earlier
- az után, ez után - after that/this; azután, ezután - thereafter, later
- az alatt, ez alatt - under that/this, during that/this; azalatt, ezalatt - meanwhile
Also, Hunniel, I looked through the Magyar Helyesírás Szabályai, but I have no idea what to look for. There isn't a single mention of amellett.
I'm not exactly sure if you think what I guess you're thinking, but: you need to remember that suffixes like -nál or -ban work differently from postpositions like mellett or előtt. Suffixes get attached and postpositions stay separate:
- Miben? - abban - amiben - amelyikben
- Minél? - annál - aminél - amelyiknél
- Mi mellett? - a mellett - ami mellett - amelyik melett
- Mi előtt? - az előtt - ami előtt - amelyik előtt
The only times that postpositions do get modified are when you construct those adverbs, like amellett, or when you make the personal (pronominal?) forms, like "next to you" etc.:
Awesome post. All I'd like to add is a correction to your example sentence ("Amellett akarok említeni, hogy az óvónők nem repülnek.")
In regards to grammar: you need the definite conjugation here -- "akarom említeni"
You also need the prefix "meg", otherwise it feels as if you wanted to repeat the fact that kindergarten teachers don't fly, over and over again. Actually no, it doesn't even express that much. It makes about as much sense as using the verb 'mention' in present continuous. So you need "meg akarom említeni".
In regards to style: 'akarok'/'akarom' in Hungarian feels in general stronger than 'I want' in English. You'd rather use 'szeretném' here, even if you were aggressive about it.
So in the end you have "amellett meg szeretném említeni, hogy..." or "amellett szeretném megemlíteni, hogy..."
(Also, I'd use "emellett" instead, even when translating "beside that", but that might be just my personal preference)
The "a mellett" works as a marker here, to mark the word that the dependent clause refers to. That way you can put the dependent clause wherever and it will always refer back to the house.
English doesn't have this flexibility. If you follow the Hungarian example and translate it as "Next to that house there is the bus, in which nobody is living", you'll get confused looks. Relative clauses need to come right after what the refer to, because English doesn't have that marker. That also means that it doesn't make much of a difference if you translate "a mellett a ház mellett" as "next to the house" or "next to that house". They would both be translated the same.