Much like barakta, I'm a native English speaker with conversational BSL that's atrophied from lack of use. Since most of my exposure these days is through video, my reception's okay (accent permitting) but my brain goes faster than my hands and I end up in a muddle.
My definition of being able to speak a language is when you can say something without translating from your native tongue, which is a watershed as far as I am concerned.
But very much this. The nature of sign languages is that they're just more natural for visual/spacial descriptions than one-dimensional speech, so I'll often find myself using BSL proforms for emphasis, even with non-signers.
I've got a shit GCSE in German, which to date has mostly been used for translating B&M instruction manuals and booking campsites. I once found myself in a
xkcd://466 situation and learned to use
ipchains with nothing but the SUSE German manpages to work from.
The reason I have a shit GCSE in German rather than the default French is because at primary school, our French teacher was more interested in talking about food than teaching us much of the language. So by the time I got to secondary - where I had a native French speaker for a form tutor as well as French lessons - I was two years behind everyone else and thoroughly lost. German, on the other hand, was taught from scratch.
That said, last time I found myself in a Dutch supermarket reading the trilinugal ingredients list on something, I found the French version most useful, so some of the food vocabulary must have stuck.
But ultimately, I'm one of those people who can only learn languages by actually using them. Which is fairly rubbish when you're
BRITISH and have to actively seek out other languages.