It seems to me that röf is the sound made by pigs - but "growl" in English is usually about animals such as dogs.
Yes, this one is specifically what pigs do. Röf-röf!
"Grunt" is not really offensive to use with people, is it? However, in Hungarian, if I say that somebody "röfög", I am comparing them to a pig.
So, careful, take this word very literally.
No, "grunt" is not offensive; it just means that someone made a non-verbal noise.
It's not a polite noise to make compared to using words, usually, but if someone does make the noise then calling that noise a "grunt" is not itself impolite.
(But in German, grunzen is as in Hungarian: pretty explicitly comparing them to a pig, and the sound is different from the kind usually called "grunt" in English in reference to a person. grummeln, brummen, knurren would be better for the noncommittal sound, though knurren is closer to "growl".)
Yes, I think it is the same in Hungarian, more of a growling reference: "morog" (longer) or "mordul" (a single grunt).
And these can be verbal, too, just not very eloquent or clear. Barely distinguishable.
Pigs both oink and grunt. They're different sounds. (But it may be that röfög refers to the oinking sound more than the grunting?)
To clarify for the Hungarian experts here, oinking is more verbal than grunting, if that makes sense.
I was with my Hungarian cousins when this lesson came up, and this was the first question - boy, did they laugh!