Spanish is pretty handy in the western U.S. Besides, Mexican food is my favorite, so it helps to be able to read the menu as well, much less understanding what type of trash talk my Mexican friends are throwing out there. Fairly easy grammatical Latin based constructs, and relatively easy vocabulary. We share a lot of common words in American English with Spanish (remember the Alamo!). It's a Latin based language. My Spanish is okay.
French is good because I have 2 kids who speak fluent French, having picked it up from spending a couple years in West Africa. It's a handy language to know even if French people are largely disgusting and smelly. Tougher grammatical Latin based constructs than Spanish, and fairly easy vocabulary but tougher than Spanish. We also share a lot of words in English with French (yeah, all that 1066 stuff). It's also a Latin based language. My French is pretty decent.
Norwegian was the next obvious language to learn because of my ancestry, etc. It's also the best Scandinavian language to learn as it isn't insane to learn like Icelandic and a working knowledge of Norwegian means you can also understand Swedish pretty well (essentially Norwegian while singing), much of Danish (essentially Norwegian with a mouth full of gravel), and a bit of Dutch (essentially Norwegian with a bunch of mispronounced words) and a little German (essentially Norwegian with mispronounced words all smashed together into one word). The grammatical setup of the language is almost identical to English (no conjugation of verbs, something that makes English people crazy when studying Spanish and French), but the vocabulary can be a little tough. Very few actual shared words with the English although tons are very similar to English words. It's a Northern Germanic language. My Norwegian is getting better, almost as good as Spanish.
English is a Western Germanic language with Dutch and German.
Icelandic, Norwegian, Swedish, and Danish are Northern Germanic languages.
Spanish, French, Portuguese, and Italian are Latin based.
I won't comment on other languages as they're all basically useless in my awesome American life, such as commie Chinese Mandarin for instance...
Duolingo is pretty good for basic introductory learning. You won't become fluent using Duolingo but you can carry on basic interaction, order food, find your way around, and read the news, etc.
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