Phillip Minden’s comment on my last post prompted me to conduct a very cursory survey of varieties of Italian to see what they have for the words fire and place. You can see the result of this in the table below. A word of warning though — these are of course orthographic forms. I haven’t been able to find any online dictionaries which give pronunciations for non-standard varieties.
Standard Italian is the only variety I have been able to find which has a voicing mismatch for the intervocalic consonant in these two words.
It occurred to me whilst doing this survey that St. Italian has been fairly resistant to lenition, compared to some other Romance languages. Take for example the Latin word-ending -atum In St. Italian this has turned up as -ato, while Castilian Spanish has -ado.
So why there is a mismatch in St. Italian fuoco and luogo remains a mystery.