Pedro,
The professor was quite right, but learning / memorising vocabularly when you're older is probably the most difficult part of the process. You can be told a word for a particular item, but unless you use it every day for a couple of weeks, it simply doesn't stick. On one of the courses I went on, one of the lessons comprised the names of 50 different body parts. What a waste of time that was. I haven't met a doctor here that doesn't have at least a passable knowledge of English, simply because a lot of the medical papers they encounter during their training are only available in that language. And in my 15 years here I've been in five different hospitals and the two closest to our home many times.
When it comes to nurses, not so good because they don't have the same intensity and depth of training. But you get to know what they want you to do, more by sign language perhaps than anything, such as "take a deep breath" just as the needle is going to go in!
Pete,
I can write it, but if it is a word I don't know, I need to see it written down, because several letters and combinations of letters sound the same. Reading is easier for me because of my deafness and that was one of the reasons I gave up formal language lessons. I have great difficulty with sibilants in any language because of my high frequency loss. It helps that 12 of the Greek letters are identical to English - that's half of the Greek alphabet, so you only have to learn another 12.
It also helps that all written letters are pronounced - no silent ones - and no double letters. But there are lots of irregular verbs.
Another thing I might mention is that in lower case Greek or its transliteration into English (or Greeklish as we call it) is that the tonos (like an acute accent in French) is used to denote upon which syllable the emphas is to be placed. That considerably helps you to get the pronunciation right, but when a place name, for instance, in written wholly in upper case, the tonos is dispensed with. Then you're on your own.
Maurice