Are questions about grammar induction on-topic here? I believe GI belongs to the subject of machine learning, but not necessarily statistics.
When I suspect a question may be off-topic for Cross Validated, I often leave a comment like this:
Welcome to the site, @user31264. This question seems to be only about
topic ______. As such it would be off-topic for CV (see our help page). If you have a substantive question about statistics, please edit to clarify; if not, this Q may have to be be closed.
However, "statistics" in this context is shorthand for statistics, machine learning, or data visualization, which is our mandate. In other words, questions about machine learning are fully on-topic here. Note that we have a machine-learning tag, which is our fourth most commonly-used tag, appended to 1469 threads (as of today). For a full list of the topics that are appropriate for Cross Validated, see What topics can I ask about here? in our help center.