be retained by the population as their normal means of expression until the 1950s, when breakthroughs in literacy and the advent of TV broadcasting made Italian become more and more widespread, usually in its regional varieties. Characteristics of regional Italian Establishing precise boundaries is very difficult in linguistics, and this operation at the limit can be accomplished for individual phenomena (such as the realization of a sound), but not for all of them: it is necessary to proceed in part by abstractions. In general, an isogloss is an imaginary line that marks the boundary of a linguistic phenomenon. The line traditionally referred to as La Spezia-Rimini (though it is currently moving to the Massa-Senigallia line) is an important isogloss for Southern Europe, which delimits a continuum of languages and dialects characterized by similar phenomena that differ from others for these same phenomena. This imaginary line is used here to define not only a boundary between dialect groups, but also between Northern regional Italian on the one hand and Central and Southern regional Italian on the other. Other well-defined areas are the Tuscan, the Extreme Southern Italian (comprising the peninsular part of Calabria, Salento and Sicily), and finally the Sardinian ones. Based on borders like La Spezia-Rimini, here are the most well-identified groups of regional Italian. Northern Italy Northern regional Italian is characterized by a different distribution of the open and closed e and o () compared to the Florentine model, particularly evident in Milan, where the open e is pronounced at the end of the word (perché ) or in the word body in closed syllable (i.e. followed by consonant: stesso ) and the closed e in word body in open syllable (i.e. not followed by consonant: bene ). Except for the extreme Ligurian Levante, in Liguria, and especially in the capital, there is the opposite phenomenon: there is a tendency to close all the e even where the Italian standard does not envisage it. In Genoa and Bologna for example the names Mattèo, Irène, Emanuèle and the name of the city itself are pronounced with the closed e; moreover, there is no difference in the pronunciation of the word pesca either to mean "peach" (standard ) and "fishing" (standard ). There is also a strong tendency to close all the e's before a nasal consonant (usually in the same syllable) so that /ɛ/ becomes /e/. Sempre (always) is pronounced