Many words of different parts of speech indicate number or quantity. Such words are called quantifiers. Examples are words such as "every", "most", "least", "some", etc. Numerals are distinguished from other quantifiers by the fact that they designate a specific number. Examples are words such as "five, ten, fifty, one hundred, etc." They may or may not be treated as a distinct part of speech; this may vary, not only with the language, but with the choice of word. For example, "dozen" serves the function of a noun, "first" serves the function of an adjective, and "twice" serves the function of an adverb. In Old Church Slavonic, the cardinal numbers 5 to 10 were feminine nouns; when quantifying a noun, that noun was declined in the genitive plural like other nouns that followed a noun of quantity (one would say the equivalent of "five of people"). In English grammar, the classification ""numeral"" (viewed as a part of speech) is reserved for those words which have distinct grammatical behavior: when a numeral modifies a noun, it may replace the article: "the/some dogs played in the park" → "twelve dogs played in the park". (Note that *"dozen dogs played in the park" is not grammatical, so "dozen" is not a numeral in this sense.) English numerals indicate cardinal numbers. However, not all words for cardinal numbers are necessarily numerals. For example, "million" is grammatically a noun, and must be preceded by an article or numeral itself.