Personal pronouns have two forms: free and bound
Free personal pronoun
Personal pronouns have an independent form that can be used alone. This form is called free personal pronoun. Free pronouns are comparable to English «I, you, they, …».
Bound personal pronoun
Personal pronouns have a dependent form that is always used with other words. This form is called bound personal pronoun. English doesn't have such a form of pronouns. Bound pronouns, although grammatically independent, are unstressed and make syllable with their preceding word. Bound pronouns are technically called enclitic.
NOTE Through this course, personal pronouns will be written in an abbreviated form. For example, 1S stands for «1st person singular», 3P stands for «3rd person plural» and so on.