They get longer:
  • ACETYLSERYLTYROSYLSERYLISOLEUCUL-
    THREONYLSERYLPROLYLSERYLGLUTAMINYL-
    PHENYLALANYLPHENYLALANYLLEUCYL-
    SERYLSERYLVALYLTRYPTOPHYLALANYL-
    ASPARTYLPROLYLISOLEUCYLGLUTAMYLLEUCYL-
    LEUCYLASPARAGINYLVALYLCYSTEINYL-
    THREONYLSERYLSERYLLEUCYLLGLYCYL-
    ASPARAGINYLGLUTAMINYLPHENYLALANYL-
    GLUTAMINYLTHREONYLGLUTANIMYLGLUTANIMYL-
    ALANYLARGINYLTHREONYLTHREONYL-
    GLUTAMINYLVALYLGLUTAMINYLGLUTAMINYL-
    PHENYLALANYLSERYLGLUTAMINYLVALYL-
    TRYPTOPHYLLYSYLPROLYLPHENYLALANYL-
    PROLYLGLUTANIMYLSERYLTHREONYLVALYL-
    ARGINYLPHENYLALANYLPROLYLGLYCYL-
    ARPARTYLVALYLTYROSYLLYSYLYLVALYLTYROSYL-
    ARGINYLTYROSYLASPARAGINYLALANYLVALYL-
    LEUCYLASPARTYLPROLYLLLEUCYLLEUCYLGLYCYL-
    THREONYLPHENYLALANYLASPARTYLTHREONYL-
    ARGINYLASPARAGINYLISOLEUCYL-
    ISOLEUCYLGLUTAMYLVALYLGLUTAMYL-
    ASPARAGINYLGLUTAMINYLGLUTAMINYLSERYL-
    PROLYLTHREONYLALANYLGLUTAMINYL-
    THREONYLLEUCYLASPARTYLALANYLTHREONYL-
    ARGINYLLARGINYLVALYLASPARTYLASPARTYL-
    ALANYLTHREONYLVALYLALANYLISOLEUCYL-
    ARGINYLSERYLALANYLASPARAGINYLISOLEUCYL-
    ARAGINYLISOLEUCYLVALYLASPARAGINYL-
    GLUTAMYLLEUCYLVALYLARGINYLGLYCYL-
    THREONYLGLYCYLLEUCYLTYROSYLASPARAGINYL-
    GLUTANIMYLASPARAGINYLTHREONYL-
    PHENYLALANYLGLUTAMYLSERYLMETHIONYL-
    SERGLYCYLLEUCYLLEUCYLVALYLTRYPTOPHYL-
    THREONYLSERYLALANYLPROLYLALANYLSERINE
    (1,185 letters) the tobacco mosaic virus, dahlemense strain. Probably not in any dictionary, and there certainly are molecules with longer names, but this is believed to be the longest that is actually used, thus qualifying as an word of the English language.
  • KLIKAKLAKKAKLASKAKLOPATZKLAT-
    SCHABATTACREPPYCROTTYGRADDAHSEMMISHSAM-
    MINOUITHAPPLUDDYAAPPLADDYPKONPKOT
    (100 letters) A word coined by James Joyce in Finnegans Wake; the sound of crashing glass. There are 9 other 100 letter words in the book, another can be found under its writeup.
  • HONORIFICABILITUDINITATIBUS (27 letters) Another coined by Shakespeare, and used in Love's Labour's Lost. More entertaining than the last because it instantly brings to mind many, many plays corpsing at the point which the actor concerned simply gives up.
  • ULTRAANTIDISESTABLISHMENTARIANISM (33 letters and perhaps a bit of a cheat, but nonetheless a legitimate word)
  • PSEUDOANTIDISESTABLISHMENTARIANISM (34 letters and I'm sorry)
  • QUINTOQUADAGINTILLION (21 letters) 10^138
...and one that perhaps needs its own node, ULTRACREPIDARIANISM - being in the habit of giving advice or opinions about things you know nothing about. I can see it being linked to many of my future write ups.