I've always found backshifting to be one of the most challenging parts of English grammar. My current issue involves using it in questions and negations.
Recently, I got into a conversation about Russia with a guy, who clearly lacked knowledge on the topic, and as a result appeared ignorant. I then asked him:
"Why do you make it sound like Russia is some backward hellhole?"
To which he replied:
"I didn't say Russia is backward"
And here my problem ensues. For some reason I feel like he should have said "I didn't say Russia was backward", though I don't have any idea why. It just sounds more idiomatic to my non-native ear.
Another similar issue struck me during some other conversation. This time, when talking about some comic book characters, the girl I was talking to asked me:
What did you say his name was?
Although I deem it correct, I immediately started to wonder: would "What did you say his name is?" be as viable in this case?
Slight edit: what about the utterance "I had no idea you were/are this tall!"? The same applies, i.e. "were" seems more fitting?
Of course, if you manage to find any other problems with my grammar, I'd be really glad if you could point them out.