The word 'say' is correct and usable in written English. You can use it when you want to indicate that someone spoke, or to introduce a quote. Example sentence: She said, "I'm looking forward to it.".
I couldn't say.
What more can I say?
Who can say?
When we are on the tube, occasionally I have to say to a member of the public that my son is autistic and that I'm sorry he is staring.
"There will be some circumstances in which it's right for public bodies, for example at the border, at airport security, to say there is a practical necessity for asking somebody to remove a veil.
"But I say to every parent, family member and friend of the children that my Government will do everything in its power to bring them home".
"That will likely lead, I'm sorry to say, to some people resigning from the government or being fired.
Ludwig does not simply clarify my doubts with English writing, it enlightens my writing with new possibilities
Simone Ivan Conte
Software Engineer at Adobe, UK