Romance languages
Vowel prosthesis

In Late Latin a prosthetic vowel /i/ (lowered to /e/ in most languages) was inserted at the beginning of any word that began with /s/ (referred to as s impura) and a voiceless consonant (#sC- > isC-):

While Western Romance words fused the prosthetic vowel with the word, cognates in Eastern Romance and southern Italo-Romance did not, e.g. Italian scrivere, spada, spirito, Stefano, and stato, Romanian scrie, spată, spirit, Ștefan and stat. In Italian, syllabification rules were preserved instead by vowel-final articles, thus feminine spada as la spada, but instead of rendering the masculine *il stato, lo stato came to be the norm. Though receding at present, Italian once had a prosthetic /i/ maintaining /s/ syllable-final if a consonant preceded such clusters, so that 'in Switzerland' was in Svizzera. Some speakers still use the prothetic productively, and it is fossilized in a few set locutions such as in ispecie 'especially' or per iscritto 'in writing' (a form whose survival may have been buttressed in part by the word iscritto < Latin īnscrīptus).
keywords:letter_frequency