The hidden subconscious - more on language acquisition

I am coming to the conclusion that language acquisition is mainly mindset and exposure rather than talent driven. If I was dating a German and imagining a long-term future here, I'd probably actually make an effort. As it is I go to class each week for 1.5 hours because company J. is paying for it, it's private lessons from Berlitz with only me in the class, and it's during work hours. I spend around an hour each week on homework, mainly because I rather like the teacher and would feel bad by attempting nothing.

A few weeks back, I was talking to my Spanish colleague, whom I rarely get to speak to these days. My Spanish is quite comfortable, I have facilitated meetings in Spanish where I am the only non-native speaker, I've done meetings where the other speakers know almost no English, and I am able to read and discuss in Spanish high level topics like religion and philosophy. My exposure to Spanish these days is limited to a handful of work colleagues with whom I interact occasionally and 30 min per week in the car when I catch a Spanish news broadcast on Monday nights after Polish class. When I speak and read it, however, it's pretty well cemented. There is no longer 'lead time' while I get back into the feel of speaking it and I can read a newspaper pre-coffee without thinking.

Imagine my absolute surprise, then, when I am speaking to my Spanish colleague and some German words sneak right into the sentence. It was like they were slipping over the Polish border under the cover of night. The construct of the sentence was Spanish as were the bulk of the words, but 'wie immer' slipped right in, in place of the Spanish equivalent. As it is I don't really like the sounds of German in general and the best you'll get out of me on a good day is that I will listen to your German spiel and then respond in English to you if you are someone in my office. If I'm in tiny town of B I will move around completely in German on Saturdays, although it's often of a Turkish flavor over here.

Then over a weekend I was at a vegetarian restaurant in Koeln and picked up a soya hot chocolate on the way out. I was in line behind some people so it was taking a few minutes. While I was waiting, I could hear the coffeebar woman talking with a customer sitting at the counter and they were talking in Spain Spanish. I started off my order in German as that is what I am used to doing here, but midway it converted to Spanish automatically, I think because I was listening to the ladies.

The woman pauses for half a second, somehow understanding my half-baked sentence and then responds to me in Spanish. I carry on a conversation for some minutes with the customer in Spanish. But again, every once and a while a German word started to creep in, perhaps because I had spent some hours the previous night mainly around German speakers, and also speaking German.

My inability to control such slippages mainly tells me that the influence of living here is quite heavy.