A computer language that has a long learning curve, but allegedly makes one more productive when they finally get over the learning hump.
Also used to mean a language likely to be useful throughout a career, as in "Language XXX is not a career language," meaning that it helps us here at this job, but is no use in finding the next job.
One of the assumptions behind them is that somebody is going to use such a languages for a long time and use it a lot, so that the learning curve is justified. Another way of saying this is the assumption that Big Investment == Big Turnaround.
I consider Perl and Java to be in these categories. Sometimes simple languages turn into CareerLanguages when a lot of features are added over time. There seems to be a point where the language steward is more concerned about keeping existing developers happy than obtaining new ones.
Or, perhaps the language steward is more concerned with meeting requirements and fixing bugs, than keeping any developers happy. Result: a language nobody outside the company would ever want to touch with a 10-megabyte pole.
Regrettably, TechnologyChurn tends to decrease the usefulness of a CareerLanguage and indeed one's CareerSkill?s. Witness MicrosoftDotNet and ComponentObjectModel. No longer is it enough to be a Perl Programmer or a CeePlusPlus programmer. Your big investment doesn't lead to big turnaround, it just leads to another opportunity to start over again every 18 months with new jargon, new APIs, and new workarounds... but little actual improvement in the tools.
The concept of a CareerLanguage is in peril where there is SoftwareAgeism.
-- MarkSchumann
CommonLisp is often held out as a CareerLanguage, at least by the people accused of being SmugLispWeenies.
The AiWinter seems to have reduced the number (but not the quality?) of individual careers available? But still CommonLisp or SchemeLanguage are held out as things to learn simply to expand your toolbox.
See also: ProfessionEqualsJobPlusEducation, MainstreamInfluenceOfFunctionalLanguages
Another of these epic languages is ProgressLanguage. Great database, great language, high productivity but ...
no career future.
:-(