advocated for the "Medium Style", which later became the basis of the modern Russian standard language. Consonants Most consonants can represent both "soft" (palatalized, represented in the IPA with a ) and "hard" consonant phonemes. If consonant letters are followed by vowel letters, the soft/hard quality of the consonant depends on whether the vowel is meant to follow "hard" consonants or "soft" consonants ; see below. A soft sign indicates palatalization of the preceding consonant without adding a vowel. However, in modern Russian six consonant phonemes do not have phonemically distinct "soft" and "hard" variants (except in foreign proper names) and do not change "softness" in the presence of other letters: are always hard; are always soft. (Before 1950 Russian linguists considered a semivowel rather than a consonant.) See Russian phonology for details. Vowels The Russian alphabet contains 10 vowel letters. They are grouped into soft and hard vowels. The soft vowels, , either indicate a preceding palatalized consonant, or (with the exception of ) are iotated (pronounced with a preceding ) in all other cases. The IPA vowels shown are a guideline only and sometimes are realized as different sounds, particularly when unstressed. However, may be used in words of foreign origin without palatalization (), and is often realized as between soft consonants, such as in ('toy ball'). Details about individual vowels is an old Proto-Slavic close central vowel, thought to have been preserved better in modern Russian than in other Slavic languages. It was originally nasalized in certain positions: Old Russian ; Modern Russian ('rock'). Its written form developed as follows: + → → . was introduced in 1708 to distinguish the non-iotated/non-palatalizing from the iotated/palatalizing one. The original usage had been for the uniotated , or for the iotated, but had dropped out of use by the sixteenth century. In native Russian words, is found only at the beginnings of a few words 'this (is) (m./f./n.)', 'these', 'what a', 'that way', 'sort of', and interjections like 'hey') or in compound words (e.g. 'therefore' = + , where is the dative case of ). In words that come from foreign languages in which iotated is uncommon or nonexistent (such as English), is usually written in the beginning of words and after vowels except (e.g. , 'poet'), and after and consonants. However, the pronunciation is inconsistent. Many of these borrowed words, especially monosyllables, words ending in and many words