The verbs "znać", "wiedzieć", "umieć" and "potrafić"
In Polish, there are 4 verbs that share a similar meaning: "znać", "wiedzieć", "umieć" and "potrafić". They all translate into the English verb "to know". Their meanings partially overlap, but they are used with different prepositions (thus forcing other cases of the object in the phrase) and form different phrasal structures. The verb "znać" has additionally a slightly different meaning, when used as the reflexive verb "znać się".
Here is a short description of how to distinguish them in Polish.
Concerns knowledge on a particular subject. The verb "wiedzieć" can also be an introduction to a dependent clause.
- to know a single piece of information
- to know a lot or everything in a very narrow or specific field of knowledge
- to be aware of something specific
- to be familiar with something specific
- to know about something, to know that something is...
- Wiem, co to słowo znaczy = I know what this word means
- On wie, co to jest alfabet = He knows what the alphabet is (but it does not say whether he knows the letters of the alphabet or knows how to read)
- Ona wie, jak się ubrać na każdą okazję = She knows how to dress for every occasion
- Wiem, kim jest John (John in Nominative)= I know who is John
- Wiem gdzie jest Warszawa (Nominative) = I know where Warsaw is
- Wiem, co myślisz = I know what you think
- Wiem, co ludzie o mnie mówią = I know what people say about me
- Wiem, co to oznacza = I know what it means
- Nie wiem nic o tej sprawie = I know nothing on that matter
- Wiem, że tu jesteś = I know that you are here
- Wiemy, co zrobiłeś = We know what you have done
Concerns wide knowledge or general acquaintance. The verb "znać" cannot be an introduction to a dependent clause.
- to have knowledge on a given matter, to know something
- to know some part of required knowledge
- to be felt, to be perceived, to be shown
- Znam to słowo = I know this word
- On zna wszystkie litery alfabetu = He knows all the letters of alphabet (but it does not say whether he is able to use them)
- Znam Johna (John in Accusative)= I know John
- Znam Warszawę (Accusative) = I know Warsaw (this may mean any or all of the following: I know what is interesting in the city, I know its topography, I know how to live and work there, I know its history, people who live there, I know how to spend time and have fun in the city)
- Znam twoje myśli (Accusative) = I know your thoughts, I know what you think (see the example above)
- Znam opinie na mój temat = I know the opinions about me, I know what people think of me (see the example above)
- Nie znam detali tej sprawy (Genitive, because of negation) = I do not know the details of this matter (but, presumably, I know at least something on that matter)
- Znam ten wiersz na pamięć = I know this poem by heart (in context of just knowing a poem)
- Na jego twarzy znać było zmęczenie = His face showed tiredness
- W powietrzu znać było napięcie = There was tension in the air
- to know oneself ("znać siebie")
- to know each other ("znać się ze sobą ...")
- to maintain an acquaintance with someone ("znać się z ...")
- to keep relationship between some persons ("znać się z ...")
- to have a vast knowledge on some subject ("znać się na ...")
- Znam sie z Johnem (John in Instrumental) = I know John, or better I've known John, I'm friends with John, I have a relationship with John
- Znam się na tym = I am familiar with that, I have a sound expertise on that
- to be able to make something, that requires knowledge on a given matter
- to be able to do something, thanks to some knowledge - but also skill, training etc.
- to be able to do or make something better than most other people would
- to have some/partial knowledge on a given matter, especially in context of an exam
- a shorter option for wiedzieć jak = "to know how (to)"
- Umiem używać tego słowa ("słowa" is "słowo" singular in Genitive, because "używać" normally requires Genitive)= I know how to use this word
- On umie czytać = He knows how to read
- Ona umie się ubrać na każdą okazję = She knows how to dress for every occasion
- Umiem rozmawiać z Johnem (John in Instrumental because of preposition "z") = I know how to talk to John
- Umiem poruszać się po Warszawie (Warszawie in locative, because of preposition "po") = I know how to move around Warsaw, I know how to make my way through Warsaw
- Umiem wyrazić swoją opinię na ten temat (Opinia in Accusative because of verb "wyrazić") = I know how to express my opinion on that subject
- Umiem coś powiedzieć na temat detali tej sprawy = I am able to say something on the details of that matter
- Umiem mówić po polsku = I can speak Polish
- Umiem prowadzić konwersację w 5 językach = I am able to carry on a conversation in 5 languages
- Umiem strzelać z pistoletu = I can shoot a gun
- Umiem przyrządzić kurczaka = I know how to prepare chicken
- Umiem zrobić pizze = I can make pizza
- Umiem ten wiersz na pamięć = I know this poem by heart (in context of e.g. school homework)
- Umiem wszystko do egzaminu = I know everything needed to pass the exam
- Czego Jaś się nie nauczył, tego Jan nie będzie umiał = What little Johny has not learnt, the grown up John will not know; As the twig is bent, so grows the tree
You may replace the verb "umieć" by "potrafić". The difference is that with "umieć" there is more stress put to what one can do. With "potrafić" there is more stress on the abilities or customs of a person.
- Potrafię używać tego słowa ("słowa" is "słowo" singular in Genitive, because "używać" normally requires Genitive) = I do know how to use this word
- On potrafi czytać = He does know how to read
But the verb "potrafić" has also other meanings.
- to reach some limit in one's behaviour or to attain some state (in positive sense: e.g. state of proficiency - or negative sense, eg. state of abnegation).
- about machines or devices: to be designed/built in order to do/make something
- On potrafi gadać godzinami = He is able to jaw for hours
- On potrafi ustrzelić ptaka w locie = He is capable of hitting a bird in flight
- Ten komputer potrafi wykonać nasze obliczenia = This computer is capable of performing our calculations
- Ta kamera potrafi widzieć w ciemności = This camera is able to see in the dark
I am not a linguist, but an engineer who loves his mother tongue. If there is something missing above, something is wrong or unclear, please do not hesitate to suggest corrections.
You may also want to check:
- Conjugation of Verbs in Polish
- Aspect of Verbs in Polish, Verbs of Singular, Multiple and Completed actions
- What is Genitive Case Useful For
- The Mysterious Pronouns swój, swoja, swoje
- The Meaningful Position of Adjective
- Translating "and" into Polish explained
- English "that" is sometimes Polish ten, sometimes tamten
- The versatile word to
- The Logical Accent in Polish
One small correction:
Umiem/potrafię używać to słowo. => Umiem/potrafię używać (kogo? czego?) tego słowa.
"Używać" is one of those verbs that require Genitive in this case instead of Accusative, similarly to:
udzielić (kogo? czego?) wywiadu = to give an interview
nienawidzić (kogo? czego?) poniedziałków = to hate Mondays
dolać (kogo? czego?) mleka = to pour out some more milk
uniknąć (kogo? czego?) kary = to escape punishment
I'd say it bears a bit different meaning. You say "wiem, jak + verb" when you say that you know how to do something, and "umiem", when you say that you have the ability to do something.
"Wiem, jak obsługiwać komputer" - "I know how to use the computer, you needn't tell me what to do".
"Umiem obsługiwać komputer" - "I know how to use the computer, I've done this several times already".
"Znam drogę do sklepu" - "I know the way to the shop" "Wiem, jak dojść do sklepu" - "I know how to get to the shop (means almost the same as the first sentence, but yeah, the first one is stylistically slightly better)". "Umiem dojść do sklepu" - "I can get to the shop (on my own)".
If you're looking for a stylistically better option, use "potrafić" - the better version of "umieć".
The answer is not easy. It depends on the model of Polish grammar that we take into consideration. According to the most popular, the simplified model by prof. Tokarski, there are 18 groups of verbs depending on the verb ending + irregular verbs. You can find the tables of conjugation according to this model (with some sample verbs only) here
If you want to go deeper into the details, you can read about it here.
And in this thread I described how to find the grammatical forms of any word.