Growing up I never gave much importance to learning other languages. I spent most of my youth in Texas and therefor had some passive exposure to Spanish and managed to pick up a bit here and there, but I never really put much effort into learning any languages. In fact, when required to study a foreign language in High School, I picked Latin precisely because nobody would ever really expect me to speak it.
Living with George for 14 years has resulted in nearly daily exposure to Cantonese, but to be honest it is usually limited to vocabulary related to food, me being a jerk, or my inability to keep the toilet clean. Visiting her family in Hong Kong I usually have to get thru slightly more complicated sentences related to how much I like Hong Kong, when I will move there, and when I will be having children.
I've been in France now for about a year and a half. When I moved here I could barely say hello in French, but now I think I can pretty much say anything I need to say. I still speak like a 3 year old, have a horrible accent, and rely on short games of charades to make up for my limited vocabulary, but I get by.
French grammar is not too bad, and Chinese (Cantonese) has probably the simplest grammar of any language on the planet, but both of these language are really hard to pronounce for my 'merican tongue. Sounds that I am just not used to making, or hearing, result in some words that are clearly different words for a native speaker sounding almost exactly the same to me. Usually the context of the complete sentence will make it clear what word was meant, but not always. One of the harder sounds in French for us English speakers is the French 'u', which is a sound somewhere between the vowel sound in "loop" and the vowel sound in "ewe", and when I first started studying French, I was watching an educational program teaching french adjectives of location which included the important examples below:
Le lait est au-dessus du pain dans le réfrigérateur.
(the milk is above the bread in the fridge)
Le pain est au-dessous du lait dans le réfrigérateur.
(the bread is below the milk in the fridge).
The only difference between these sentences is the ending vowel sounds in the french words for above (au-dessus) and below (au-dessous), and I must have rewinded and rewatched this video 25 times before realizing that I was simply never going to know if the milk was above or below the bread in the fridge, and that hopefully my life never depends on me solving any French riddles regarding the relative locations of objects.
I haven't yet come across any situations in French where I have made a complete idiot of myself by mispronouncing something, although I have certainly had cases where I was more benignly misunderstood. I've honestly been a bit disappointed by this, as I am always reminded of American movies where the hero's basic knowledge of a foreign language leads to all kinds of hilarious misunderstandings. Like John Candy's character in Splash when he and Tom Hanks are pretending to be Swedish scientists so they can sneak in and rescue Darryl Hannah. As only Hollywood luck would have it, one of the guards is half Swedish and he questions our heroes in Swedish asking what they are doing there, to which John Candy mistakenly replies "Hey babe, I got a 12 inch penis".
I have absolutely no knowledge of the Swedish language, but I have to imagine one would need to speak the language quite well to respond in such a way, and that it would be difficult to mistakenly refer to your genitals when trying to say something more appropriate like "We are here to see the mermaid".
But maybe not. In my infrequent and not very efficient efforts to improve my spoken Cantonese, I will point to random objects around the house and ask George to tell me how to say it. Last night I randomly pointed to George's breasts, and she responded hung bo (胸部), which to me sounded exactly the same as a word I already knew--horrible (hung bo 恐怖)--with the only difference in pronunciation being the tone at which one pronounces the word. To make this even worse, the word for "very" in Cantonese is the same as the word for "good", and so to my ears that cannot hear all the different tones in a language like Cantonese, the phrase "very horrible" (好恐怖) has pretty much the same pronunciation as the sentence "nice breasts" (好胸部).
I can totally see myself walking down the street in Hong Kong, and some women comes running around a corner covered in blood or something screaming about a terrible accident, and in my efforts to say something supportive like "oh, how horrible" I might just inappropriately compliment her on her woman parts.