I asked about the construction ‘tu me manque’ (‘I miss you’) and got some speedy and helpful answers.
I was confused because it looks like it means ‘You miss me’. I was thinking of when I learnt French at school, and I thought we learnt that to say ‘I need an X’ we should say ‘Je manque un X’, meaning something like ‘I lack an X’. It turns out that this is basically right, although there should be a ‘de’ in there too. This is the construction with ‘de’ + a direct object, and it means ‘to lack something’.
But there is also this other construction, used when you mean ‘to miss a person or place or thing’, in which the subject is the missed thing, and the person feeling the lack is the indirect object. ‘Me’ in ‘tu me manques’ is dative (= ‘to/from me’), not accusative (=’me’), and it means ‘you are missing from me’, as the gazillions of tumblr-language-romantics have pointed out.
It’s similar, I think, to the construction ‘me gusta X’ in Spanish, which means something like ‘X is pleasing to me’.
Never thought about these constructions in terms of datives before but now it makes so much sense.