As a poor example:
Person A: ‘I really liked cats when I was a child.’
Person B: ‘When you say you “liked cats”, could you tell me more?’
Person A: ‘Blah blah.’
I’m really wondering about the tense of ‘when you say’ here. Should it be ‘When you said’? Is there a name for this type of construction or how the verb ‘say’ is acting here? I’m falling flat on my face trying to find out. I ran it through a parts of speech tagger and got ‘say’ as singular present, but that isn’t specific enough for me to find usage examples like this.
I understand it’d be ‘said’ if it was something like ‘when you said that, what did you mean?’ But how about when the conversation is currently happening?
If we were computers, that is, if we tried to analyze the structure of the sentence without thinking about what the speaker probably meant1, we would say that the sentence is in the present tense and the imperative mood and that the meaning – that is, the most strictly literal meaning – is: on all occasions when you say “I like cats,” please also tell me more.
This is grammatical, but a very strange request. The same structure would make more sense with different actions: when you get up to give your presentation, could you first say your name and the title of your report?
But we know that’s not what the speaker meant. What they meant was: When you say you liked cats [hmm, let me think about what I want to say…] Could you tell me more about that? or When you say you liked cats [what exactly do you mean?] Could you tell me more?
A more polished version of the question would be: Tell me more about what you mean/t when you say/said you liked cats – the difference between past and present there is almost entirely meaningless. That is, both have essentially the same meaning.
1 As I understand it, this is not actually how modern computerized language parsing works. Neural semantic parsing or machine translation actually do try to consider the likelihood of a possible meaning.