How to politely disagree

Being able to challenge someone's opinion or disagree with what they have said, is particularly tricky as what is polite changes depending on the culture of the person you are speaking to. Even within English native speakers there is a difference. Generally speaking Americans are more direct than British people. As a British person I can sometimes find this rude. In the opposite direction, American friends have previously complained that I wasn't clear.

The below list of phrases are the middle ground that should work in most international business situations (you can also download the  PDF here).  However, if you are dealing with one particular culture, particularly if they are based in their own country and don't have that much international experience, I would recommend researching this issue to see what is the norm in this country. As well as reducing the risk of you offending someone, it should also help you understand them better.

Disagreeing fully:
I have a different opinion.
I see it differently.    
You said……….however isn’t it the case that…….
I feel a better approach would be…..
 
Disagreeing partially:
I agree to a certain extent but……
I see what you mean however…..
 
Further investigating the point:
I think there are other things that haven’t been considered. Such as…………
I think it’s more complicated than that.
Is that an assumption or is there data that backs this up?
But have you considered all the factors? For example, what about……
If I could just add to that.
 
Interrupting and dealing with interruptions:
If I could just jump in for a moment…
If I could just finish what I was saying (and then we will come back to that.)