Punctuation Input on Touchscreen Keyboards: Analyzing Frequency of Use and Costs

Non-alphanumeric symbols are rarely considered in text input research even though some punctuation is more frequent than the least common English letters. In this paper, we first evaluate punctuation frequency in two contrasting sources (Twitter and Google N-Grams). We then present a controlled study to compare existing techniques for ten-finger punctuation input on touchscreens: (1) the status quo, where punctuation symbols are stored on an alternate keyboard layer, and (2) an approach where users draw punctuation symbols atop the Qwerty keyboard itself [3]. Our findings show patterns in punctuation use (e.g., comparing mobile and desktop input), and highlight the cost of mode-switching to enter punctuation marks. Author