I think what the above poster was referring to was the cultural connotations that are immediately invoked by a word or phrase that isn't really transmissible to someone not familiar with the language and its culture. The example of "bouquet" was likely to touch on the idea that the literal translation of the word would be more akin to their example of "bunch of flowers". Since the word has now integrated into English, there is an immediate understanding that you're not just referring to a bunch of flowers, but something meant to be aesthetically pleasing and usually to signify an event of some importance. I suppose the English language did handle the word, but it did so by just integrating the word, not by translating it.

The response to the parent comment was more to debate that there are a lot of words, concepts, and idioms that may carry an actual translation or similar concept in another, but the translations fail to capture the immediacy of the idea conveyed by the original word or phrase. It's not to say that there is no way to understand or interpret these bits of language unless you're a native speaker, it's that in many cases you lose a lot of the meaning without the cultural context surrounding it.

Culture and language are pretty inseparable; it's why transliteration is often frowned upon when doing translation works, and localization is considered important to helping the audience understand without imparting too high of a burden of knowledge of their part. Sometimes this burden of knowledge is simply unavoidable. But the ability of a word or phrase to evoke a specific idea/image/feeling in one language and to not do so in another is not impossible. If you know anyone for whom English is a second language (and has not spent extended time in the US), try to explain why "cut the cheese" is funny in English. They may understand conceptually that there is a rude meaning to the phrase, but I'm willing to bet they'd be more than happy to tell you that they'll cut the cheese in the kitchen.

But a floral arrangement can be of various shapes, laid out in a wreath or across a table right? At least as I've heard it used, bouquet doesn't really refer to a wreath or other designs. Maybe I'm splitting nonexistent hairs.