Edit: doh. I forgot there is a word for that: portmanteau.
FWIW, "situational comedy" is not something that a english speaking person would normally say (or even necessarily understand without context), and likewise the literal Portuguese translation ("comédia situacional") is extremely unlikely to evoke a mental image of "Friends" the way that "sitcom" does in English. If I had to attempt to explain what "sitcom" means to a brazilian person, I might instead say something like "série de comédia americana", which translates literally to "american comedy series".
In Japanese, there's the word "pasocon" (portmanteau of personal computer). Obviously here in the west, nobody would use that combination of words that way.
So I think which portmanteaus exist in a language is a function of the originating culture, which is an interesting phenomenon on its own.
The more interesting part of Japanese portmanteaus is the use of the first two mora from each word, where English speakers would try to fit head to tail, like “persoputer” or something. But I guess in an agglutinative language, the end of a word is a much fuzzier concept.
Hmm, I think abbreviations are more common. Case in point, personal computer is usually abbreviated to PC.
But PC nowadays has a connotation of a non-Apple computer. Just goes to show how much nuance culture bring into the picture!