Either we can go back to the first miscreant or it is something in us or each person discovers it independently or it's a combination of some or all of these.
It is, of course, something we learn - we aren't born as miscreants. And of course we may learn from others that have also been up to no good, but that isn't the same as being born up to no good (regardless of who we are or where we are born etc, etc) which would be the situation if being up to no good were hereditary.
Also you talk about language. Not a good analogy since wrong doing is world wide.
So is language - all human cultures have languages as learned rather than hereditary behaviour - it is just that the language in different cultures is different. I suspect exactly the same is true for wrong-doing - different cultures perceive different types of action as wrong, but this is a learned not an inherited trait and is basically cultural as whether something is deemed right or wrong is societal not inherent.
There is no learning environment where a child can learn sinlessness.
But that already implies that a baby is sinful and has to learn sinlessness. I think the opposite is true, a baby isn't born bad, but may go on to engage in wrong doing as learned behaviour. However, even if it is likely that the child will do something wrong at some point it is morally bankrupt to assume they already have done something wrong before the fact. It is akin to the grossest form of criminal profiling and random stop and search - christianity regards everyone as having already sinned regardless of whether they have done anything wrong or indeed will ever do anything wrong.