Yo Kass answered
The translation of 'I know' in Italian is io so.
io so is the first person singular of the verb sapere, meaning 'to know'. The noun that derives from this is the noun sapienza - which means 'knowledge', and is also the name of the largest Italian University situated in the heart of Rome: La Sapienza.
'io so' and 'lo so'
However, if you were using the phrase 'I know' as a response to convey knowing something specific, you'd say lo so.
For example, if you were busy playing video games in your bedroom and were suddenly disturbed by your mother shouting piercingly up the stairs 'You've got lots of homework to do!', you might choose to avoid a protracted conversation by replying 'I know!'. In this case, you would use the Italian lo so which is actually the shortened form of io lo so, but still makes sense and sounds much more natural without the pronoun.
Not to be confused with 'io sono'
When listening to native speakers conversing, there will be certain complexities that may confuse someone who is less than fluent in Italian. The phrase io sono is one such example: io sono is the first person singular of the verb essere which means 'to be'- therefore io sono is the Italian equivalent of 'I am'. Unfortunately, in conversational Italian, it is often reduced to io so' or even just so' - as in so' troppo stanco (I'm so tired) - which can obviously cause some confusion!
In popular culture
Whilst on the subject of confusion, one example of io so (as in 'I know') in popular culture is the rather confusingly-titled 1982 film featuring Alberto Sordi, and entitled io so che tu sai che io so which translates to 'I know that you know that I know'.
io so is the first person singular of the verb sapere, meaning 'to know'. The noun that derives from this is the noun sapienza - which means 'knowledge', and is also the name of the largest Italian University situated in the heart of Rome: La Sapienza.
'io so' and 'lo so'
However, if you were using the phrase 'I know' as a response to convey knowing something specific, you'd say lo so.
For example, if you were busy playing video games in your bedroom and were suddenly disturbed by your mother shouting piercingly up the stairs 'You've got lots of homework to do!', you might choose to avoid a protracted conversation by replying 'I know!'. In this case, you would use the Italian lo so which is actually the shortened form of io lo so, but still makes sense and sounds much more natural without the pronoun.
Not to be confused with 'io sono'
When listening to native speakers conversing, there will be certain complexities that may confuse someone who is less than fluent in Italian. The phrase io sono is one such example: io sono is the first person singular of the verb essere which means 'to be'- therefore io sono is the Italian equivalent of 'I am'. Unfortunately, in conversational Italian, it is often reduced to io so' or even just so' - as in so' troppo stanco (I'm so tired) - which can obviously cause some confusion!
In popular culture
Whilst on the subject of confusion, one example of io so (as in 'I know') in popular culture is the rather confusingly-titled 1982 film featuring Alberto Sordi, and entitled io so che tu sai che io so which translates to 'I know that you know that I know'.
