 Unlike British English, American English typically uses "an" before "herb", since the "h" in this word is silent for most Americans.The correct usage in respect of the term "hereditary peer" was the subject of an amendment debated in the UK Parliament.The word "some" can be viewed as functionally a plural of "a/an" in that, for example, "an apple" never means more than one apple but "give me "some" apples" indicates more than one is desired but without specifying a quantity.