Since we have moved to China my English has definitely deteriorated. I won’t even mention my Dutch as that has been going down the tube for a long time (I found myself saying ‘helpte’ recently, which obviously only makes sense to those who speak Dutch and even then it may not).
I’m not sure if it has something to do with trying to make myself understood in English or if it is just because I am learning a new language which has a different structure (although sometimes it feels like it has none at all). Maybe it’s a combination of both. For example saying ‘more better’, instead of just saying it the correct way sometimes helps. In Chinese the adjective does not change, instead they add a word so for example faster is translated as ‘more fast’. The more Chinese I learn, the more I can hear it coming through when Chinese people speak English.