Don't forget that the use - or non-use - of an article is not an optional nicety. Articles carry meaning, and failure to use an article correctly can change the meaning of what you are saying. Of course, it all depends why you are learning to speak English. If a lost tourist stops a passerby in the street in London and says 'Where is station?', that's not a problem. We understand what they mean, and it doesn't matter that they sound childish. However, if we encounter a non-native English speaker who doesn't know or care how to use articles correctly in a professional, academic or business context, that is an entirely different situation. If you want to be taken seriously as an intelligent-sounding adult, you need to use articles properly. If you don't use articles, it sounds like 'pidgin English' or 'baby talk' to us. If you don't mind sounding like a two-year-old, that's fine.

I am not a native English speaker, but since both of my native languages (German and French) have the same concept, I immediately recognize a missing "a" or "the" in an English text. In most cases I can tell from the context which article is missing, but sometimes it is not entirely clear. In any case, missing articles make a text look (or sound) quite clumsy to me..

If they are missing, we will most often know what you are saying. But we will also recognize you as a non-native speaker which is ok. I think this is something that can take many years to master.

It does _not_ cause a problem in understanding. It just makes you sound "like a foreign speaker." If you just want to speak fluent conversational English, it is OK. Over time, if you want to "speak good English," you should try to master the use of "the" and "a," but you do not need to do it at first.

I know articles are tricky, but they're not just there to confuse language learners. They convey meaning, especially to people whose native language is English. When someone leaves them out, it's a tiny bit disorienting. Even if the information (whether it is a specific object, how many items, etc.) is somewhere else in the sentence - that's not where I'm expecting to hear that information and it takes a few moments for me to catch up to the rest of your sentence (the parts that you think are important) while I figure out that bit of information. If we're lucky, I'll figure it out, eventually. If we're unlucky, I won't understand you at all. Leaving out articles will get in the way of your communication. And that's the whole point of learning another language, to be understood. Also, without articles, English sounds "caveman"-like. It lacks polish. I understand your pain - right now, I'm struggling with gendered declensions in Russian (seriously, who came up with those rules?); they're driving me crazy. But I know that if I want to be able to talk to someone and not confuse them, I need to be able to use the noun properly.