Russian orthography (Russian: правописа́ние, tr. pravopisaniye, IPA: [prəvəpʲɪˈsanʲɪjə]) is formally considered to encompass spelling (Russian: орфогра́фия, tr. orfografiya, IPA: [ɐrfɐˈɡrafʲɪjə]) and punctuation (Russian: пунктуа́ция, tr. punktuatsiya, IPA: [pʊnktʊˈat͡sɨjə]). Russian spelling, which is quite phonemic in practice, is a mix of the morphological and phonetic principles, with a few etymological or historic forms, and occasional grammatical differentiation. The punctuation, originally based on Byzantine Greek, was in the seventeenth and eighteenth centuries reformulated on the French and German models. The IPA transcription attempts to reflect vowel reduction when not under stress. The sounds that are presented are those of the standard language; other dialects may have noticeably different pronunciation for the vowels.