We hear in colloquial Bohemian já sem, instead of já jsem. My sme instead of my jsme etc. This dropping of j in present indicative of the verb býti is inadmissible in correct Bohemian.
Moreover: jsem—am, but sem, here, hither.
Declension of se for all three genders. Sing. and Plur.
| Nom. and Voc. | se |
| Objective | se, sebe |
| Possessive | sebe |
| Dative | sobě, si |
| Locative | sobě |
| Instrumental | sebou |
Reflexive pronoun (and its possessive form svůj, svá, své) refer to the subject of the sentence or clause in which they stand.
Examples: Koupil jsem (já) knihu pro tebe. I bought the book for you. Koupil jsem knihu pro sebe. I bought the book for myself. Pomyslil si. He thought to himself. My se tu dřeme a on si tam leží v chládku. Here we exert ourselves and he is lying there in the shade. Nemysli si to! Don’t imagine that! Mluví o tobě. Mluví o sobě. He speaks of you. He speaks of himself. Zná sám sebe. He knows himself. U samých dveří. At the very door. (Sám, alone, self, very, used here to emphasize sebe). To se rozumí samo sebou. That’s understood (by itself or on account of its very nature).
Mě, tě, mi, ti, si are enclitics. They cannot be used at the beginning of the sentence nor can they be employed after preposition. Therefore ke mně, pro tebe, u sebe, v tobě etc. Mně, tobě, tebe, sebe, are stronger forms. They are to be used at the beginning of sentences.
Mně štěstí přálo. Fortune smiled upon me.