First of all, I want to say that I am not a native English speaker, but I can say that my English level is very high. I can write professional content, I have done a lot of written assignments regarding Network security, including the cryctografic process of how the currency such as bitcoins work. I am pretty interested in this subject, as a network engineer, encryption and network currency is a big subject. I can talk and write really great content about it.
PD: I am native Spanish speaker but I learned to speak English at the school online "openenglish"