Reflexive pronouns 1. 'se' is a short unstressed form of 'sebe' which is a reflexive personal pronoun in accusative 2. 'si' is a short unstressed form of 'sobě' which is a reflexive personal pronoun in dative Učím se mluvit česky. - I learn/am learning Czech. Učím češtinu. - I teach/am teaching Czech. They are used with a verb that reflects on the subject itself. - myslet si, posadit se, bát se, umínit si... The first sentence is with a reflexive pronoun because you learn for/to yourself. The second you teach to someone else. Another examples: - Píšu si deník. - I keep a diary. (the words I write in the diary are for myself) - Co si myslíš? - What do you think? (what is your own personal opinion?)