I've heard esperantists mention "La Leĝo de Tonjo" but I'm not sure what it means. Can anybody explain?
The Leĝo de Tonjo is a humorous law mocking the fact that a large portion of conversations in Esperanto end up getting derailed by a discussion about grammar. The original text of the law is:
Ju pli reta diskuto en Esperanto longas, la probableco ke ĝi deflankiĝos al diskuto pri gramatikaĵoj aŭ pri la uzata vortigo des pli (asimptote) proksimiĝas al 1.
A rough translation would be:
The longer an internet discussion in Esperanto gets, the more the probability that it will get side-tracked into a discussion about grammatical points or the usage of a word approaches 1
It is written in an overly scientific style to make it seem more official, but it is just stating that a long internet conversation in Esperanto is bound to eventually end up with a pedantic talk about the language usage.
It is inspired by Godwin's law which is as follows:
As an online discussion grows longer, the probability of a comparison involving Nazism or Hitler approaches 1
This makes a similar point that any internet conversation will eventually make a reference to Nazism or Hitler. I guess in the case of conversations in Esperanto that likely means the conversation will first become a heated debate about grammar and then if it continues then one of the parties will angrily accuse the other of behaving like Hitler.