The variety of Sicilian spoken in Pantelleria has developed a progressive construction which involves pronominal subject clitics. This is striking in many respects. Firstly, on a Romance scale, subject clitics are usually regarded as characteristic for varieties spoken north of Florence. Secondly, in none of the central Romance dialects where subject clitics are known to occur do these convey progressive meaning. The latter seems to be unusual on a larger scale too, as none of the strategies for progressive marking reported in the relevant literature on linguistic typology seems to be directly comparable with the one displayed by Pantiscu. Besides, the results of the present study have some consequences for grammaticalization theory, as they suggest that recent revisions of Hopper & Traugott's `cline of grammaticalization' are not on the right track and that the cline originally proposed should rather be revised so as to include the distinction between syntactic and phonological cliticization.