Abstract
It is known that many of us hear an “inner voice” during silent reading. We call this auditory processing “phonological coding,” and its processing time is estimated by a simple linear equation: [120×Sy + 80×Cn] millisecond; where Sy is the number of syllables and Cn is the number of consonants in a target text. Subtitles on TV or videos are made for viewers to read out while the speech action is on the screen. For example, BBC’s guideline says, “The recommended subtitle speed is 160-180 words-per-minute,” and TED’s guideline says “Keep the subtitle reading speed at a maximum of 21 characters / second”. In this report, we compared TED Talks’ subtitle length in time and their predicted duration time for phonological coding calculated by the linear equation. The average length of fifty thousand TED Talks’ subtitles included in two hundred videos is measured to be 2.95 second, and calculated by the equation to be 2.88 second. Quantifying the difference between two groups of measured and calculated values, Cohen’s d effect size is 0.07. These findings suggest the appropriateness of the equation to predict the time for phonological coding, and also might suggest that TED viewers would be able to read out the subtitles just before they vanish away.
