Since I first learned I had got the job in Sicily, my Spanish has suffered. The day after the job interview, I was at a Spanish/English language exchange, and I kept dropping words of Italian into my Spanish. The weird thing is that my Spanish was a million times stronger than my Italian then, but somehow my brain had switched "mode".
Obviously, living in Italy for four months has only served to intensify this, with my Spanish now being half-hidden behind fairly broken bits of Italian. My assumption for a long time was that my problem was in my accent -- I still speak Italian with a bit of a Spanish twang. This belief was bolstered by the fact that my Catalan, while being very, very weak from lack of use, didn't seem so badly affected. The Catalan accent is very, very different from Spanish and Italian.
However, I was at a Couchsurfing meeting on Friday night which changed my mind. There was an Andalusian tourist visiting, and when I spoke to her, my accent was more different from the one I use in Italian than I had expected. My brain started playing tricks on me, and I had difficulty speaking Italian when she was in my line-of-sight, and for a while I was wobbling between Italian and Spanish.
But that's not the important thing.
When I was speaking Italian, I got into much deeper and more complex conversations than I normally would, and rather than jamming up as I hit the limits of my Italian, I was automatically switching to Spanish to fill in the gaps. Now, I wasn't just importing words or grammar rules from Spanish into Italian -- no, I was switching into Spanish; conjugations, pronouns and all. As I became aware I was doing this, it dawned on me that I'd been doing it for my whole stay, but normally I'd just not thought about it too much and fallen back to English.
This is a bit of a new sensation... or actually, no. The only new thing is the fact that I was unaware of it. When it was Scottish Gaelic and French, for example, it would be instantly noticeable. The difference here is that the similarity of the languages (including, but not limited to, accent) allowed it to slip through the net on occasions.
The trigger mechanism is the same, regardless of language: hit a gap in your knowledge in one language and the brain will fall back on another. The only difference lies in detection.
This makes me wonder if the only option I have now to get my Spanish back is... to learn more Italian. My theory is that filling in the main gaps in my Italian will not only stop me falling back on Spanish when I run out of Italian, but that as a consequence of this, it will reduce the strength of the linkage between the two, allowing me to speak Spanish without Italian interrupting me.
It looks like I might be practising my Italian a lot, even once I leave Italy...