Comparison between Czech and English languages

Saturday night I went to the Catholic Bible Study in Besednice (with the parents of the family I lived with). Then in the morning I got up at 5am to catch the only morning bus to České Budějovice (so that I could go to my new church). On the bus was another person from the Catholic Bible study, a doctor/physician dealing with heart diseases. He talked to me in Czech as we travelled, much of which I didn't understand. He has actually learned English and showed me an article from a medical journal written in English. I think I understood more of the conversation than the article...