As an onset, the cluster + voiceless consonant is inherently unstable. Phonetically, word-internal "s"+C normally syllabifies as "rospo" 'toad', "Trastevere" (neighborhood of Rome). Phonetic syllabification of the cluster also occurs at word boundaries if a vowel precedes it without pause, e.g. "la storia" 'the history', implying the same syllable break at the structural level, , thus always latent due to the extrasyllabic , but unrealized phonetically unless a vowel precedes. A competing analysis accepts that while the syllabification is accurate historically, modern retreat of "i"-prosthesis before word initial +C (e.g. erstwhile "con isforzo" 'with effort' has generally given way to "con sforzo") suggests that the structure is now underdetermined, with occurrence of or variable "according to the context and the idiosyncratic behaviour of the speakers."