Translation of emphatisch

It would be an advantage if you could send it via DHL, UPS or another Currier, because the parcel was lost once when we sent it with regular mail. Please send me a reference number after you send it.
I've been working on and off on the dictionary during the entire week, and I'll spend some more hours on it this coming weekend. Sometimes he would get a bit mixed up and use formal Castilian sometimes instead of informal.
It was a short but nice letter from you. I hope that you had a great vacation. I realize that I should practice at least half an hour a day. Vocabulix helps to learn Spanish vocabulary.