I found this suggestion for a CAPTCHA challenge for people who want to use the internet funny (via The Daily What).
If you failed to answer correctly, you would see this:
If you are concerned that this might disadvantage not only native speakers of English (apparently among them also designers of Apple’s “auto-correct” feature) who should know how to use apostrophes properly, but don’t, but also non-native speakers of English, this CAPTCHA from Facebook suggests that, as the internet brings people together across language divides, all speakers of all languages may face moments when language presents a challenge for internet use:
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