I know a linguist whose English has precisely these bilabial trills as allophones of /p/. It's an idiolect, of course.

Thanks! This looks like an interesting article, and I will read it. It might be a bit too narrow for the purpose of the BA course, but I might use it elsewhere.

I notice that the version installed on our university computers is 2020, so I guess that explains it.

I haven’t noticed any changes in Acrobat Reader?

Norwegian dialects have both 'klein' and 'klen', btw.

The North Germanic variants 'klein' and 'klen' are probably the result of borrowing the word several times from Low German varieties with and without a diphthong.