When a person who is speaking Catalonian faces me directly and I can observe their mouth all the time, I understand about 95% of what they are saying. But if I stop looking at the speaker’s mouth, I understand only about 5%.
Curiously, it’s not like this with any other language. Seeing the speaker’s mouth does absolutely nothing for me in French or German*, for instance. Neither does it help with Portuguese.
* These are languages that I studied in the past.
Clarissa's Blog 