How can one write for a living and spell like this? English is not my mother tongue and yet I now the difference between they're and their, it's vs. its.
Or is this the result of poor speech-recognition software?
So, to somebody who learned English as a child -- and is therefore aurally dominant -- the words "they're", "there", and "their" will all basically occupy an overlapping space in their mind. Somebody who learned English later will use textbooks to support the process; Things like contractions will be give special emphasis, etc.
It doesn't seem likely that non-native speakers are better general spellers than native speakers; but it's possible that some words are especially difficult for native speakers and not for non-native ones.
Are you aware of existing studies on that subject?
1. Van Orden, Guy C. (1987). A ROWS is a ROSE: Spelling, sound and reading.
2. Binder, K. & Borecki, C. (2007). The use of phonological, orthographic, and contextual information during reading.
3. Ota, M., Hartsuiker, R. J., & Haywood, S. L. (2010). Is a FAN always FUN?
Full texts for all of those are available online.