The average English-speaker has about 50,000 words in their mind. But how do they find the right one in 600 milliseconds?

A Bangor University expert believes the constant battle for prominence between words like "cat" and "dog" could help to explain.

Dr Gary Oppenheim, of the university's Language Production Lab, is working to reveal the "algorithms and architectures" behind vocabulary.

He explained to BBC Wales how words which share "semantic features" are constantly jockeying for position.

Story by Max Evans

Video by Michael Burgess and Philip John