Usage of Going and Being
As you would expect there is a verb difference in Polish when it comes to talking about 'going' somewhere and 'being' somewhere. After all, these clearly represent different actions and states of affairs. However, as we have seen before with Polish, it's not just the verb that needs changing, both nouns and adjectives incur conjugations as well. While it is possible to learn these nuances from careful study of the individual cases in Polish, for some instances of common phrasal language it can be easier to look at examples.
The sentence structures of 'going' and 'being' are so common that it's probably a good idea to look at how each one alters the various parts of speech individually, rather than just approach these sentences with case knowledge and hope to get it right that way. When we look at examples of each here, I will indicate the relevant case, so it's easy for you to go back and check up on the rules you've seen, but it's also a good idea to repeat the examples in your head to get the sounds of the sentences; it's this that will stimulate a natural ability to conjugate off cuff.
Let's take two examples of Polish prepositions that are very common in both, sentences of location, and sentences of motion: Na (literally meaning 'on'), and w (literally meaning 'in'). What's curious is although these mean virtually the same thing in each type of sentence they require specific grammar in each case to be produced correctly.
Saying 'Going' With Na and W
When we use the verb ‘going to’ (whether by transport or walking, and remember these are different in Polish [iść/jechać]) followed by one of the above prepositions, it's necessary to follow it with nouns and adjectives in the accusative case. This means there's a whole host of associated endings that will distinguish it from using these prepositions to locate an item.
For example, if I wanted to say 'I am going to the airport', I would use the preposition 'na', (in Polish we say literally 'I am going on the airport'), followed by the noun 'lotnisko', which has no ending change (because it's a neuter noun in the accusative case).
Again, if I wanted to say that I was travelling (by transport) to a conference, I would use the same sentence with the verb 'jadę' (I am going) and preposition 'na', and the accusative feminine noun ending konferencję (conference).
With the w preposition, the same applies. I could say literally 'I am going in the mountains', using the preposition with plural accusative endings: idę w góry.
Saying 'Being' With Na and W
When it comes to saying 'being', that is locating something (including yourself) physically, a different set of endings is required in Polish. Here, we need to adopt the locative case.
As above, if I wanted to say 'to be in the airport', I would adopt the locative ending of lotnisko, which, being a neuter singular noun is lotnisku: być na lotnisku.
Similarly if I wanted to say 'to be in the mountains', I would use the locative case ending for the noun góry (mountains) along with the verb 'to be' in the infinitive: być w górach.
Remember that it's important to make the distinction between these two ostensibly similar ways of talking about yourself and objects in Polish, as each requires a different case, the locative or the accusative (though this will also depend on the preposition in question). These cases in turn will require different endings for their adjectives and nouns, singulars and plurals; so watch out!