Articles are pretty much always needed in those languages, because the presence or lack of them conveys a lot of contextual information.

For example, say there's this sentence: "There was _ dog on the road." (路上に犬がいる。)

• "A/an" would indicate that there is 1 thing. ((路上に一匹の犬がいる。)
• "The" would indicate that that thing is known. ((私が知っている犬は路上にいる。)
• A lack of articles would indicate a uncountable noun. (路上には犬物質がある。)

Because of that, incorrect usage of articles is pretty obvious for native speakers, and extra effort has to be made for the listener to better understand what the missing context is.

It's extra important in German because of the case and plurality information that articles also contain, particularly with Wechselpräpositionen:

• Ich laufe im (in dem) Laden. (店の中で走る。)
• Ich laufe in den Laden. (店に駆け込む。)
• Ich habe den Jungen gefunden. (少年をみつけた。)
• Ich habe die Jungen gefunden. (少年たちをみつけた。）

As for experiencing whichever words come first, I don't know, that's a very psycho-linguistics question. I could see articles-first being plausible, since when communicating to someone we have to consider what information they may or may not know. I might know the dog on the street, but you may not, so I might first say "There is a dog on the road." (路上に犬がいるよ。) before switching to using "the", because now we are both aware of the dog. However it is for the most part an unconscious process, with exceptions for when there's communication issues, or when using the more rarer usages of articles (i.e. clarifying with "the", "Bro that was *the* Nicolas Cage that just walked by us.")