K       +/!100
    Python  sum(range(100))
    Haskell sum [0..99]
    Rust    (0..100).sum()
    Ruby    (0..99).sum

There are plenty of ultra-concise languages for toy problems like these; they are called ‘golfing languages’. Ultimately it's a bit pointless since most of the time people aren't playing code golf.

(The issue with setting everything to obscure ultra-compressed keywords isn't that it's not possible to learn those keywords, but that most of the time programming is done over specific and customized domains with larger and problem-specific vocabularies.)