Translation:We do not leave from the school, but from Kati.
Doesn't "Katitól" also mean "from Kati's" / "from Kati's place" / "from chez Kati"? I don't remember addressing this with -hoz and -nál, but all of those include a "chez" sense, don't they? Katinál vagyunk: we're at Kati's place. Katihoz megyek: I'm going to Kati's (place). Or am I completely wrong about this?
"We do not leave [from] [the] school, but [from] Kati."
Words in brackets are optional.
Although "to leave" when used with a person is a little different than with a building; with a building, it simply means to not be on the premises anymore, whereas with a person, it means to break up with them, or in some other way sever an interpersonal relationship. (Which, in other words, would make this sentence a Type-2 zeugma)
If you want to use "to depart", however, the "from"s become mandatory, as the verb is strictly intransitive:
"We do not leave from [the] school, but from Kati."
In both cases the "the" is optional, although the meaning is of course slightly but not drastically different. Without the "the", the school in question would be assumed to be wherever it is that you usually go to school. With the "the", the school in question would be assumed to be a previously mentioned school and is therefore determined by context.
"to start" so rarely means "to leave" that it would throw a lot of people off, and furthermore it requires context to establish where the person is going, which is absent here.
OK, thanks, that confirms what I was feeling.
The thing is here, with the Hungarian sentence, that it speaks about a departure. We are getting on our way somewhere. Maybe a road trip. So the point is not leaving (the) school, or Kati, but rather defining the point of departure for the trip. The meeting point.
We do not start from the school, but from [Carine / Carine's / Carines / Catherine / Catherine's / Catherines / Karine / Karine's / Karines / Kathi / Kathi's / Kathis / Kathy / Kathy's / Kathys / Kati / Kati's / Katis] [. / place.]
It's so much easier to type Kati, folks!