It was a short way of writing a different spelling of the words all correct. Some foreign-born people wrote all correct as o-l-l k-o-r-r-e-c-t, and used the letters O.K.

VOA: special.2010.02.28

It turns out there's a new function strlen S-T-R-L-E-N that you probably have not used yet called strlen, S-T-R-L-E-N, programmers early on and still like to be succinct but communicates sufficiently what they mean.

结果这里有个新的函数,你可能没有使用过，叫做，早期的和现在的程序员喜欢简洁地,但是能充分的传达他们的意思。

哈佛公开课 - 计算机科学课程节选

If you think of two towns down here, Brive,b-r-i-v-e,famous for its rugby, and Tulle,t-u-l-l-e,which is a capital.

如果你可以想起来这儿的两个城镇,布瑞福,b-r-i-v-e,以英式橄榄球运动而负有盛名,图勒,t-u-l-l-e,是一个省的首府

耶鲁公开课 - 1871年后的法国课程节选