In the FreeBSD port the "plaintextedit" example has the spell checking code enabled, but no actual spell checking is performed.

The qTox project also enables spell checking using sonnet and spell checking doesn't work, at least on FreeBSD: https://github.com/qTox/qTox

Once spell checking is enabled it has to be performed. If there is a reason that it can't work, the error message should be printed on the standard output. Currently it silently doesn't work and doesn't print anything.