While the actual question is already answered (language names in German are neuter), your approach for decision-making, visible in

> Programmiersprache is feminine, does that actually mean [...]

shows a misunderstanding that even native German speakers suffer from, namely that gender would follow the gender of [some category](https://en.wikipedia.org/wiki/Categorization) name.

The grammatical gender of the collective name (or category name) gives no indication of the gender of the noun for the things it generalizes. But the category itself may rule the gender. See for example:

Der Baum: *m*

* die Fichte
* die Kiefer
* *most* trees are feminine (this is such a gender rule)
* aber
  * *der* Mammutbaum (compound noun, last word *Baum* dictates gender)
  * *der* Ahorn (one of the exceptions – thanks to bakunin for [the the comment!](https://german.stackexchange.com/questions/53014/may-i-say-die-kotlin-programming-language#comment172781_58823)) 
  * *der* Ginkgo (exotic tree whose name [dates back to a transliteration or spelling mistake around 1690](https://de.wikipedia.org/wiki/Ginkgo#Etymologie_und_Nomenklatur))


Die Krankheit: *f*

* der Husten
* der Scharlach
* der Schnupfen
* das Asthma
* die Gicht

Das Gefäß: *n*

* der Eimer
* die Tonne
* das Fass

For further information, see

* [Grammatical gender in German - Wikipedia](https://en.wikipedia.org/wiki/Grammatical_gender_in_German)
  * especially the rules in section [#Noun meanings](https://en.wikipedia.org/wiki/Grammatical_gender_in_German#Noun_meanings)