I can understand youBut I do not think it is only a problem of Russian. I have to communicate with English-speaking customers from the US, and I often feel exactly the same as you do. I know all the professional terms, I try to construct my phrases properly. But when it comes to some complex logic involved I feel them struggle to understand me. Not everything can be easily translated from one language to another one. There are lots of tricky expressions if not to count compound sentences, conditions, subjunctions, tense nuances etc. Phrasal verbs drive me crazy as well.