1) "Mhm" is simply a general answer/expression showing general agreement/satisifcation. I am lazy, therefore I choose to use a generic all-purpose response usually, rather than wasting precious time in creating some precise one for each situation.
2) "Earf" is a little joke from another corner of the internet long ago. I shall not bother to explain it thoroughly, but it originates from some poking of fun at the English language while developing names for fictional planets to test some stuff.
3) My line of various "Russia" / "Russian" bots originate from a bot "Siberia" which I so named for its white colouration reflecting the cold north of Russia. In several bots I used the out coming colour of mutation for the original coded line as the source for a name. It has no relation to you or your mother Botsareus, the world does not revolve around you. Additionally, I too have a lisp. I once was far worse at speaking then your mother undoubtedly was.
4) Finally, take a logical look at this. How could I be poking fun at your mother, I do not know her, I do not know you in real life, and I am not from Russia.
You however do clearly post jibes. My previous ventures here I was younger, and less skilled with my communication in some areas. I never came with malicious intent and am unable to see any clear interpretation which would show such intent, however I lack to see how many of your posts could be interpreted with anything but such intent.
On the occasional times I shall undoubtedly venture back here (As I do truly like the program and its concept) I do ask you keep your insults and so forth into your head.