difference in usypiac

what is the difference in usypiać and zasypiać, which is pf and imp.
how do i say i fell aspleep, some said it is usnęłem.

thanks

chaza

means lull a baby or kill an animal.

uśpić psa w schronisku.


means go asleep.

Both are imperfective.

'Zasypiać' means 'to fall asleep' and is intransitive (you are the one who is falling asleep). The perfective counterpart is 'zasnąć' or 'usnąć' (like in the example someone told you).

'Usypiać' means 'to make someone to sleep' and is transitive (someone else is the one who is falling asleep). The prefective counterpart is 'uśpić'

So in your example 'usnąłem' (or 'zasnąłem') means I fell asleep and it's 1st sing. past of perf. usnąć (or 'zasnąć' resp.), however, 'zasnąć' is used more often.

Cinek

thanks cinek, that was a great explanation.

chaza

Great explanation. Usypiać means sth like 'to put down' (an animal). Zasypiać is more like 'to fall asleep' as in 'zasypiam' (I'm falling asleep).

perhaps because of not so nice connotations of 'uśpić' in colloquial Polish the perfective form of 'usypiać' is often 'uspać' when the talk is about a child (or a person) - I don't think it is somehow established dictionary wise though - in this perspective 'uśpić kogoś' is rather to put someone to sleep with use of some herb or medicine especially when done against the person's will (but also as a medical procedure as before an operation)

there is also a phrase (phrasal verb???) in Polish - 'uśpić czyjąś czujność' - to put someone of his guard (literally put someone's vigillance to sleep)

I've never heard it. It must by a regional form. But you're right that 'uspić' sometimes sounds bad.
We use 'położyć kogoś spać' in such cases instead.

Cinek

'uspać' is not correct at all. it does not exist.

What might the expression mean then "sypki czas"? Unfortunately, I no longer have the context, nor do I even remember where I read/heard/saw it-:)