It is a very good article. The many different English accents also makes it harder. I am an English speaker and of course the different English accents are fine. But, while I feel comfortable with French in France, I feel hopeless in Quebec. Similarly, I feel OK in Spain and lost with many Latinos. All three of these languages are spoken in many countries and the diversity of accents among native speakers can make it even more challenging. I use speach recognition software at work and it has a hard time understanding my speach, while native speakers never do. I think this just reflects the way context makes up for slurred words. The article mentions very helpful exercises.