[mcswell]

I am a linguist, and I agree. But it does complicate the grammar to allow for these other options. (I haven't studied leet speak, but my impression is that it's more a matter of vocabulary than grammar, and vocabulary is relatively easy to add.)

For the record, the parser I worked on ended up having the "interesting" rules removed, leaving it as a tool for finding sentences that didn't conform to a Basic English grammar with a controlled vocabulary--and used to QC aircraft repair manuals, which need to be read by non-native English speakers.