1731: C vs. K (& Q vs. G) Sep 10, 2019

In very old Latin writings, C, K, and Q were all used to represent the sounds /k/ and /g/, those two not yet distinguished in writing. This is mostly the same as in English now, and similarly certain variants were prefered in certain contexts, such as Q before a rounded vowel (hence Qu-). C eventually replaced K in most words, one exception being 'Kalend' (calend), and G was invented off of C—that's why they look so similar—and in places where the Latin alphabet was adopted, like Roman England or places where the Romance languages are spoken today. Elsewhere, like in Germanic areas or Eastern Europe, this was not so, and they kept K. This was influenced also by runic letters, but only so far.

For more on English spelling, watch the newest video here, or for the history of letters, click here.