Sep 4, 2019
Luckily, scales for measuring spoken fluency and overall proficiency exist. “Fluency is an abstract concept, so we assign observable variables,” explains Daniel Morgan. Two of the most reliable factors are “speech rate” and “utterance length”. Speech rate can be defined as how much (effective) language you’re producing over time, for example how many syllables per minute. Utterance length is, as an average, how much you can produce between disfluencies (e.g. a pause or hesitation). You could look at accuracy as being subsumed into fluency, in terms of grammatical accuracy, lexical choice, pronunciation, and precision.”
"How do we measure language fluency?” from BBC Future