Bri is an undergraduate science student attending a sustainability expo to explore possible areas for future research and network with others interested in the topic. 

At the expo there is a professional 'speed dating' session, where participants spend a few minutes talking to someone, then move on to talk to someone else. Bri enjoys talking to the first few people, meeting other students, industry professionals, and people working in non-government organisations. Their final partner for the session is a lecturer who researches solar panel designs. While a little intimidated at speaking to someone senior with so much experience, Bri is excited as the topic is something they are very interested in. They explain a bit about their studies and interests, and then their partner starts to talk enthusiastically about their work. Bri can clearly hear their partner as they have found a quiet part of the room for their chat, and the partner is using relatively simple language as they have spoken to several different people already. Bri quickly gets lost as the person speaking very quickly and has a strong accent that means there are a few words Bri can't understand. At the end of the time, Bri thanks them and walks away a bit disappointed as they hadn't managed to learn anything about the research. 

What factor most affected the effectiveness of the communication between Bri and their last speeddating partner?