In RP, the distinction between ‘penis’ /?pi?n?s/ and ‘peonies’ /?pi??n?z/ is very clear.
However, in Scottish English, the /?/ in the latter word is omitted, so in my current mixture of RP and Scottish English the two words become almost homophonous: /?pi?n?s/ vs. /?pi?n?z/.
However, applying the standard rules of Scottish English (not of Scots!) would make the difference somewhat clearer – you would expect the difference to be /’pin?s/ [?pin?s] vs. /?pine#z/ [?pine?z].
The difference is even bigger, though.
Something happens to the first vowel in peonies, so the difference is actually [?pin?s] vs. [?pi?ne?z], as if it were /?pi#ne#z/ (almost like a hypothetical compound *pea-nays).
I wonder what’s going on – in Scottish English vowel length is normally predictable if you know the morphology of the word.