We get in trouble when we make assumptions. Foreigners sometimes get nasty surprises when they think that no one around them can speak their language. My late partner was an Arabic Linguist in the Air Force. He could could glean enough from the conversation to tell what they were saying. As part of his training he was taught to recognize languages that he couldn't translate so they could be routed to someone who could. It can be very effective to say one word to signal you know what was said.
This young man's mistake is that he missed more than one clue about the ladies. The beer probably didn't help. One of the problems in the United Kingdom is that there are dozens of dialects. Americans haven't a clue but many in the UK can identify the difference between Scouse and Geordie.
He may also have made incorrect assumptions about the ladies in general leading to them beating him soundly.