Spanish pronouns in some ways work quite differently from their English counterparts. Subject pronouns are often omitted, and object pronouns come in clitic and non-clitic forms. When used as clitics, object pronouns can appear as proclitics that come before the verb or as enclitics attached to the end of the verb in different linguistic environments. There is also regional variation in the use of pronouns, particularly the use of the informal second-person singular vos and the informal second-person plural vosotros.