I suspect if I went back over my old blog posts I’d find that I’ve written quite a lot of guff over the years, which is why I never read anything more than 2 weeks old. Anyway, I wrote one called “Prestável vs. Prestativo” 5 years ago in which I said Prestativo was used for helpful people and Prestável for helpful things.
Apparently this was bollocks though, a reliable source has informed me. I mean, the source didn’t use that word obviously, but that was the gist. I must have had some reason for saying so at the time, but I can’t remember what prompted it. Anyway, Prestativo and Prestável are pretty close synonyms. Prestável may have slightly more of a subservient tinge to it, but these things probably vary from place to place and time to time, so probably take that with a pinch of salt too.
I looked both up on Linguee to see if there were any differences in the way they are used. Not really. It gives slightly different patterns but there’s a lot of overlap. Most of the examples in prestativo seem to have the adjective directly applied to the person
Nosso motorista, Yuri, é muito prestativo e para cada vez que quero tirar fotos.
and prestável tended to be weighted towards modifying an attitude or action of some kind held by a person or organisation
Para que isto se torne realidade, conto com a acção prestável, incentivadora e fiscalizadora de todas as Instituições europeias.
But it’s definitely not an ironclad rule and there are counterexamples for both, so it’s pobably just be randomness in what Linguee has on its first page when I looked at it and I’m definitely not going to read anything into that since I messed it up so badly last time!
Luso 