Syntactic gemination, or syntactic doubling, is an external sandhi phenomenon in Italian, some Western Romance languages, and Finnish. It consists in the lengthening of the initial consonant in certain contexts. The phenomenon is variously referred to in English as word-initial gemination, phonosyntactic consonantal gemination, as well as under the native Italian terms: raddoppiamento sintattico, raddoppiamento fonosintattico, raddoppiamento iniziale, rafforzamento iniziale
Italian
"Syntactic" means that gemination spans word boundaries, as opposed to word-internal geminate consonants as in "cat" or "year". In Standard Italian, syntactic doubling occurs after the following words :
all stressed monosyllables and many unstressed monosyllables: a, blu, che, chi, dà, do, e, è, fa, fra, fu, già, ha, ho, là, ma, me, né, o, può, qua, qui, re, sa, sé, so, sto, su, tra, tre, tu, va
*Example: Parigi è una città bellissima, 'Paris is a very beautiful city'
some paroxytone words : come, dove, qualche, sopra
*Example: Come va?, 'How are you?'
Articles, clitic pronouns and various particles do not cause doubling in Standard Italian. Phonetic results such as occasional /il kane/ → 'the dog' in colloquial speech are transparent cases of synchronicassimilation. The cases of doubling are commonly classified as "stress-induced doubling" and "lexical". Lexical syntactic doubling has been explained as a development, initiating as straightforward synchronic assimilation of word-final consonants to the initial consonant of the following word, subsequently reinterpreted as gemination prompts after terminal consonants were lost in the evolution from Latin to Italian. Thus resulting from assimilation of /-d#k-/ in Latin ad casam in casual speech persists today as a casa with , with no present-day clue of its origin or of why a casa has the geminate but la casa does not. Stress-induced word-initial gemination conforms to phonetic structure of Italian syllables: stressed vowels in Italian are phonetically long in open syllables, short in syllables closed by a consonant; final stressed vowels are by nature short in Italian, thus attract lengthening of a following consonant to close the syllable. In città di mare 'seaside city', the short final vowel of città thus produces . In some phonemic transcriptions, such as in the Zingarelli dictionary, words that trigger syntactic gemination are marked with an asterisk: e.g. the preposition "a" is transcribed as /a*/.
Regional occurrence
Syntactic gemination is the normal native pronunciation in Tuscany, Central Italy and Southern Italy, including Sicily and Corsica. In Northern Italy speakers use it inconsistently because the feature is not present in the dialectal substratum and is not usually shown in the written languageunless a single word is produced by the fusion of two constituent words: "chi sa"-> chissà. It is not taught in normative grammar programmes in Italian schools, so many speakers are not consciously aware of its existence. Those northern speakers who do not acquire it naturally often do not try to adopt the feature.
*In particular, initial gemination may be conditioned by syntax, which determines the likelihood of pause. For example, in the phrase La volpe ne aveva mangiato metà prima di addormentarsi, there is no gemination after metà if there is even a slight pause, as prima is part of the adjunct, a sentence element that is easily isolated phonologically from the main clause within the prosodic hierarchy of the phrase.
the stressed final vowel is lengthened;
a sharp break or change occurs in the pitch on the word boundary.
There are other considerations, especially in various dialects, so that initial gemination is subject to complicated lexical, syntactic and phonological/prosodic conditions.
Finnish
In Finnish, the phenomenon is called rajageminaatio or rajakahdennus, alku- or loppukahdennus. It is triggered by certain morphemes. If the morpheme boundary is followed by a consonant, then it is doubled, if by a vowel then a long glottal stop is introduced. For example, "mene pois" is pronounced "meneppois" and "mene ulos". Following Fred Karlsson, these triggering morphemes are called x-morphemes and marked with the superscripted 'x', e.g., "sadex".
Maltese
does not itself feature syntactic gemination, but it predominantly borrows Sicilian and Italian verbs with a geminated initial consonant, e.g. kkomprenda, pperfezzjona from Italian comprendere, perfezionare. Though reinforced by native verbal morphology, this phenomenon likely goes back originally to syntactic gemination in the source languages.