Relative distribution of p and h in word initial position in Kannada. The name also somewhat playfully alludes to pH the measure, because their relative frequency can be used to assess how much of a text's vocabulary is from Halegannada (Old Kannada) vs Posagannada (Modern Kannada).
PS: Astute readers might've noticed the irony in having "h" in Hale and "p" in Posa. :-)